US president Donald Trump ordered a major increase in sanctions on Iran. Picture: AP Photo/Evan Vucci

President Donald Trump ordered a major increase in sanctions on Iran on Wednesday as Saudi Arabia displayed remnants of drones and missiles it said were used in a crippling attack on its oil sites “unquestionably sponsored” by Tehran.

Trump gave no explanation in a Twitter post announcing the order, but it followed repeated U.S. assertions that the Islamic Republic was behind Saturday’s attack and came hours after Saudi Arabia said the strike was a “test of global will”.

“I have just instructed the Secretary of the Treasury to substantially increase sanctions on the country of Iran!” he wrote.

Iran again denied involvement in the Sept. 14 raids, which hit the world’s biggest crude oil processing facility and initially knocked out half of Saudi output. Saudi Arabia is the world’s leading oil exporter.

Responsibility was claimed by Yemen’s Iran-aligned Houthi group, which on Wednesday gave more details of the raid, saying it was launched from three sites in Yemen.

In a remark that may further strain an already tense political atmosphere in the Gulf, the Houthis also said they had dozens of sites in the United Arab Emirates, Riyadh’s top Arab ally, listed as possible targets for attacks.

REUTERS