Qatar's official overseer of charities denied on Sunday that philanthropic groups in the country backed terrorism, days after U.S. President Donald Trump backed a move by some Arab states to pressure Doha over alleged militant financing.

Saudi Arabia, Bahrain, the United Arab Emirates and Egypt have tightened their squeeze on Qatar by putting dozens of figures and charities they link to the country on terrorism blacklists.

Saudi Arabia and its allies imposed an economic and diplomatic boycott on Qatar last week over what they say is the gas-rich Gulf nation's support for Iran and militant groups - charges which Doha has denied.

“The Regulatory Authority for Charitable Activities deplores the accusation that Qatari humanitarian organisations support terrorism,” the body said in an official statement.

The authority has succeeded in protecting NGOs based in Doha "from the risk of being exploited to launder money and finance terrorism,” it said.

Mr. Trump on Friday accused Qatar of being a “high level" sponsor of terrorism.

“We have to stop the funding of terrorism. I decided ... the time had come to call on Qatar to end its funding,” Mr. Trump told reporters at the White House on Friday.