People walk past a public TV screen showing a file footage of North Korean leader Kim Jong Un during a news report on North's missile launch, in Tokyo. Picture: Eugene Hoshiko/AP
People walk past a public TV screen showing a file footage of North Korean leader Kim Jong Un during a news report on North's missile launch, in Tokyo. Picture: Eugene Hoshiko/AP
People walk past a public TV screen broadcasting news of North Korea's launch of missile, in Tokyo. Picture: Eugene Hoshiko/AP
People walk past a public TV screen broadcasting news of North Korea's launch of missile, in Tokyo. Picture: Eugene Hoshiko/AP
Japan's Prime Minister Shinzo Abe speaks to reporters at his official residence in Tokyo. Picture: Hitoshi Takano/Kyodo News via AP
Japan's Prime Minister Shinzo Abe speaks to reporters at his official residence in Tokyo. Picture: Hitoshi Takano/Kyodo News via AP
A man rides a bicycle past a public TV screen broadcasting news of North Korea's launch of a missile, in Tokyo. Picture: Eugene Hoshiko/AP
A man rides a bicycle past a public TV screen broadcasting news of North Korea's launch of a missile, in Tokyo. Picture: Eugene Hoshiko/AP
A man, right, watches a public TV screen broadcasting news of North Korea's launch of a missile, in Tokyo. Picture: Eugene Hoshiko/AP
A man, right, watches a public TV screen broadcasting news of North Korea's launch of a missile, in Tokyo. Picture: Eugene Hoshiko/AP
South Korean President Moon Jae-in, second from right, speaks as he presides over a meeting of the National Security Council at the presidential Blue House in Seoul, South Korea. Picture: Yonhap via AP
South Korean President Moon Jae-in, second from right, speaks as he presides over a meeting of the National Security Council at the presidential Blue House in Seoul, South Korea. Picture: Yonhap via AP
South Korean President Moon Jae-in speaks as he presides over a meeting of the National Security Council at the presidential Blue House in Seoul, South Korea. Picture: Yonhap via AP
South Korean President Moon Jae-in speaks as he presides over a meeting of the National Security Council at the presidential Blue House in Seoul, South Korea. Picture: Yonhap via AP
In this photo provided by South Korea Defense Ministry, South Korea's Hyunmoo II ballistic missile is fired during an exercise at an undisclosed location in South Korea. Picture: South Korea Defense Ministry via AP
In this photo provided by South Korea Defense Ministry, South Korea's Hyunmoo II ballistic missile is fired during an exercise at an undisclosed location in South Korea. Picture: South Korea Defense Ministry via AP
People watch a TV screen reporting North Korea's missile launch, at the Seoul Railway Station in Seoul, South Korea. Picture: Ahn Young-joon/AP
People watch a TV screen reporting North Korea's missile launch, at the Seoul Railway Station in Seoul, South Korea. Picture: Ahn Young-joon/AP
A man distributes an extra edition of a newspaper reporting about North Korea's missile launch, at Shimbashi Station in Tokyo. Picture: Eugene Hoshiko/AP
A man distributes an extra edition of a newspaper reporting about North Korea's missile launch, at Shimbashi Station in Tokyo. Picture: Eugene Hoshiko/AP
Japanese Prime Minister Shinzo Abe, center, arrives back from India, at Haneda airport in Tokyo. Picture: Yu Nakajima/Kyodo News via AP
Japanese Prime Minister Shinzo Abe, center, arrives back from India, at Haneda airport in Tokyo. Picture: Yu Nakajima/Kyodo News via AP
TV monitors show the J-Alert (warning siren) at an office of Kyodo News in Tokyo. Picture: Toshiyuki Kuwana/Kyodo News via AP
TV monitors show the J-Alert (warning siren) at an office of Kyodo News in Tokyo. Picture: Toshiyuki Kuwana/Kyodo News via AP
Members of Japan's Self-Defense Forces have a meeting with workers at Hokkaido Government in Sapporo, following North Korea's missile launch. Picture: Masanori Takei/Kyodo News via AP
Members of Japan's Self-Defense Forces have a meeting with workers at Hokkaido Government in Sapporo, following North Korea's missile launch. Picture: Masanori Takei/Kyodo News via AP
A man distributes an extra edition of a newspaper reporting about North Korea's missile launch, at Shimbashi Station in Tokyo, Friday, Sept. 15, 2017. South Korea's military said North Korea fired an unidentified missile Friday from its capital Pyongyang that flew over Japan before landing in the northern Pacific Ocean. (AP Photo/Eugene Hoshiko)
A man distributes an extra edition of a newspaper reporting about North Korea's missile launch, at Shimbashi Station in Tokyo, Friday, Sept. 15, 2017. South Korea's military said North Korea fired an unidentified missile Friday from its capital Pyongyang that flew over Japan before landing in the northern Pacific Ocean. (AP Photo/Eugene Hoshiko)
A woman watches a TV screen showing a file footage of North Korea's missile launch, at the Seoul Railway Station in Seoul, South Korea. Picture: Ahn Young-joon/AP
A woman watches a TV screen showing a file footage of North Korea's missile launch, at the Seoul Railway Station in Seoul, South Korea. Picture: Ahn Young-joon/AP
North Korean leader Kim Jong Un waves during a military parade in Pyongyang, North Korea. File picture: Wong Maye-E/AP
North Korean leader Kim Jong Un waves during a military parade in Pyongyang, North Korea. File picture: Wong Maye-E/AP

Seoul, South Korea - North Korea conducted its longest-ever test flight of a ballistic missile Friday, sending an intermediate-range weapon hurtling over US ally Japan into the northern Pacific Ocean in a launch that signals both defiance of its rivals and a big technological advance.

Since US President Donald Trump threatened North Korea with "fire and fury" in August, the North has conducted its most powerful nuclear test, threatened to send missiles into the waters around the US Pacific island territory of Guam and launched two missiles of increasing range over Japan. July saw its first tests of intercontinental ballistic missiles that could strike deep into the US mainland when perfected.

The growing frequency, power and confidence displayed by these tests seem to confirm what governments and outside experts have long feared: North Korea is closer than ever to its goal of building a military arsenal that can viably target both US troops in Asia and the US homeland. This, in turn, is meant to allow North Korea greater military freedom in the region by raising doubts in Seoul and Tokyo that Washington would risk the annihilation of a US city to protect its Asian allies.

UN Secretary-General Antonio Guterres condemned the missile launch as a serious violation of Security Council resolutions coming less than two weeks after the North's sixth nuclear test, which also violated a UN ban.

The Security Council scheduled an emergency closed-door meeting Friday afternoon in New York. On Monday, it unanimously approved its toughest sanctions yet on North Korea over its nuclear test.

South Korea's Joint Chiefs of Staff said the latest missile travelled about 3,700 kilometres (2,300 miles) and reached a maximum height of 770 kilometres (478 miles). Guam, which is the home of important US military assets, is 3,400 kilometres (2,112 miles) away from North Korea.

North Korea's weapons tests demonstrate that it can "turn the American empire into a sea in flames through sudden surprise attack from any region and area," North Korea's Rodong Sinmun newspaper said Friday, without mentioning the latest missile test.

South Korean President Moon Jae-in, a liberal who initially pushed for talks with North Korea, said its tests currently make dialogue "impossible."

"The sanctions and pressure by the international community will only tighten so that North Korea has no choice but to take the path for genuine dialogue" for nuclear disarmament, Moon said. "If North Korea provokes us or our allies, we have the strength to smash the attempt at an early stage and inflict a level of damage it would be impossible to recover from."

North Korea has repeatedly vowed to continue its weapons tests amid what it calls US hostility — by which it means the presence of nearly 80,000 US troops stationed in Japan and South Korea. Robust international diplomacy on the issue has been stalled for years, and there's so far little sign that senior officials from North Korea and the U.S. might sit down to discuss ways to slow the North's determined march toward inclusion among the world's nuclear weapons powers.

Friday's test, which Seoul said was the 19th launch of a ballistic missile by North Korea this year, triggered sirens and warning messages in northern Japan but caused no apparent damage to aircraft or ships. It was the second missile fired over Japan in less than a month.

The missile was launched from Sunan, the location of Pyongyang's international airport and the origin of the earlier missile that flew over Japan. Analysts have speculated the new test was of the same intermediate-range missile launched in that earlier flight, the Hwasong-12, and was meant to show Washington that North Korea can hit Guam if it chose to do so.

Despite its impressive range, the missile probably still isn't accurate enough to destroy Guam's Andersen Air Force Base, said David Wright, a U.S. missile expert with the Union of Concerned Scientists. Such early generation missiles are often inaccurate because of guidance and control errors during the boost and re-entry phases as the warhead passes through the atmosphere late in flight, Wright said.

South Korea detected North Korean launch preparations Thursday, and President Moon ordered a live-fire ballistic missile drill if the launch happened. This allowed Seoul to fire its missiles only six minutes after the North's launch Friday. One of the two missiles hit a sea target about 250 kilometres (155 miles) away, which was approximately the distance to Pyongyang's Sunan, but the other failed in flight shortly after launch, South Korea's Joint Chiefs of Staff said.

North Korea initially flight-tested the Hwasong-12 and the ICBM model Hwasong-14 at highly lofted angles to reduce their range and avoid neighbouring countries.

The two launches over Japan indicate North Korea is moving toward using angles close to operational to determine whether its warheads can survive the harsh conditions of atmospheric re-entry and detonate properly.

North Korea's August launch over Japan came weeks after it threatened to fire a salvo of Hwasong-12s toward Guam and bracket the island with "enveloping" missile fire.

North Korea has been accelerating its nuclear weapons development under leader Kim Jong Un, a third-generation dictator who has conducted four of North Korea's six nuclear tests since taking power in 2011. The weapons being tested include hard-to-detect solid-fuel missiles designed to be launched from road-mobile launchers or submarines.

The sanctions approved earlier this week by the U.N. Security Council over North Korea's Sept. 3 nuclear test prohibit all textile exports and ban any country from authorizing new work permits for North Korean workers — two key sources of hard currency. They also prohibit North Korea from importing all natural gas liquids and condensates and cap its imports of crude oil and refined petroleum products.

North Korea's Foreign Ministry denounced the U.N. sanctions and said the North will "redouble its efforts to increase its strength to safeguard the country's sovereignty and right to existence."

Associated Press