WASHINGTON, Sept. 20 (Xinhua) -- U.S. President Donald Trump said on Friday that his country is imposing sanctions on Iran's national bank following attacks on Saudi Arabia's oil facilities.

Trump, speaking to reporters at the White House, claimed that the new sanctions on Tehran are the "highest sanctions ever imposed on a country."

The latest punishment came two days after Trump revealed in a tweet that he had instructed the Secretary of the Treasury to "substantially increase Sanctions on the country of Iran."

Washington has been indicating that Iran was behind Saturday's drone attacks on oil production facilities in eastern Saudi Arabia, a claim that has been strongly denied by Tehran.