Nablus - Israeli troops killed 10 Palestinians including a teenager on Wednesday in a raid on the occupied West Bank city of Nablus, while more than 80 suffered gunshot wounds, the Palestinian health ministry said.
The Israeli army said the raid targeted militant suspects "in a hideout apartment" accused of shootings in the West Bank. It said troops came under live fire but suffered no casualties.
United Nations Secretary-General António Guterres said "the situation in the occupied Palestinian territory is at its most combustible in years", with tensions "sky high" as "the peace process remains stalled".
"Our immediate priority must be to prevent further escalation, reduce tensions and restore calm," Guterres told the UN Committee on the Exercise of the Inalienable Rights of the Palestinian People.
Top Palestinian official Hussein Al Sheikh decried the incursion as a "massacre" and called for "international protection for our people".
The death toll is equal to that of an Israeli army raid last month in Jenin, further north, which was the deadliest West Bank operation since at least 2005.
The Israeli military said one of the wanted suspects who had fled the building was "neutralised", along with two others who had opened fire at the property.
The suspects and Israeli forces "exchanged fire... there were also rockets that were fired on the house" by the army, spokesman Richard Hecht told journalists.
Rocks, explosive devices and Molotov cocktails were hurled at the troops, an army statement said.
The Palestinian health ministry said those killed "as a result of the occupation's aggression on Nablus" were aged between 16 and 72.
A further 82 people were admitted to hospitals with gunshot wounds, Palestinian health officials said.
Mostafa Shaheen, a Nablus resident, said he was surprised to hear explosions at around 9.30am.
"A large number of soldiers stormed in and besieged the whole area," he said. "We kept hearing explosions and gunfire."
The wounded include Palestine TV journalist Mohammed Al Khatib, who was shot in the hand, his colleague told AFP.
The Islamic Jihad militant group said one of its commanders was killed "in a heroic battle against the Israeli occupation army and its special forces".
The Lions' Den, a militant group based in Nablus, said six of those killed were members of various Palestinian factions.
Troops withdrew from the city after three hours, an AFP journalist said.
Hailing the forces' "courage", Defence Minister Yoav Gallant said on Twitter Israel's "long arm" will reach "any terrorist".
In the afternoon, a huge crowd of mourners including armed men gathered in central Nablus for the funerals of nine of those killed, AFP correspondents said. The tenth fatality was buried in the nearby Balata refugee camp.
The Palestinian Red Crescent Society said its medics had treated 250 cases of tear gas inhalation and dozens of gunshot wounds.
The Arab League said the raid amounted to a "heinous crime".
"The occupation authorities and the far-right Israeli government are responsible for this horrible massacre," said Saeed Abu Ali, the League's assistant secretary-general for Palestinian affairs.
Neighbouring Jordan meanwhile called for calm, saying it would "work intensely with all parties to achieve this".
Saudi Arabia issued a "strong condemnation... of the Israeli occupation forces' assault", the foreign ministry said in a statement.
Since the start of this year, the Israeli-Palestinian conflict has claimed the lives of 59 Palestinian adults and children, including militants and civilians.
Nine Israeli civilians, including three children, one Ukrainian civilian and a police officer have been killed over the same period, according to an AFP tally based on official sources from both sides.
US Secretary of State Antony Blinken spoke on Saturday with Israeli Prime Minister Benjamin Netanyahu and separately with Palestinian president Mahmud Abbas, calling on both to "restore calm".
Last month's visit by Washington's top envoy to Israel and the Palestinian territories has been followed by further violence and rifts between officials.
Israel has occupied the Palestinian territory since the Six-Day War of 1967.
Last year was the deadliest year in the territory since the United Nations started tracking casualties in 2005.