"No more funding," Trump emphasized. His comments come following the diplomatic row that erupted last week between Qatar and major Middle East powers like Saudi Arabia and Egypt.
The "high level" of support — whether it be financial, logistical or moral — for terror groups originating in Doha must stop, the president said.
"I want to call on all of the nations to stop immediately supporting terrorism," Trump reiterated.
Trump thanked Saudi Arabia for hosting a "historic" summit between the US and more than 50 nations, noting that this will hopefully serve as a platform that marks "the beginning of the end of terrorism." He did not mention, however, Riyadh's well-documented role in supporting violent extremists in the Middle East and beyond.
Following the summit, Trump said, "nations came together and spoke to me about confronting Qatar over its behaviors. So we had a decision to make. Do we take the easy road or do we finally take a hard but necessary action?"
Earlier in the day, US Secretary of State Rex Tillerson said, "The Emir of Qatar has made progress in halting financial support and expelling terrorist elements from his country. But he must do more and he must do it more quickly."
Last week, Bahrain, Saudi Arabia, Egypt and the United Arab Emirates suspended diplomatic relations with Qatar over what they call the country's support for terrorism. Jordan has also downgraded ties with Qatar and shuttered Amman's Al Jazeera offices. Kuwait has stepped in to attempt to mediate the disagreement.
The Al Jazeera network, which is funded by Qatar, said it came under a massive cyber attack in the days after the diplomatic blockade against Qatar was launched.
