In a series of posts on Twitter on Tuesday, Trump referenced Qatar when he said leaders of the Middle East have stated that they "would take a hard line on funding extremism".
"During my recent trip to the Middle East I stated that there can no longer be funding of Radical Ideology. Leaders pointed to Qatar - look!" Trump said.
"So good to see the Saudi Arabia visit with the King and 50 countries already paying off. They said they would take a hard line on funding...
...extremism, and all reference was pointing to Qatar. Perhaps this will be the beginning of the end to the horror of terrorism!"
The Qatari government had no immediate response to Trump's tweet.
Meanwhile, the Pentagon said it is grateful to Qatar for support of US military presence and "enduring commitment to regional security".
Qatar and Saudi along with five other countries are currently locked in a diplomatic dispute over Doha's role in the region.
Conflicting US message
Al Jazeera's Patty Culhane, reporting from Washington, DC, said the latest post of Trump only complicates efforts to defuse the situation.
"I can tell you from the defence department perspective, from the secretary of state perspective, they don't want this [dispute] to continue.
"They want the sides to de-escalate. This couple of tweets does exactly the opposite," Culhane said.
Trump's latest statement shows he is not in line with people in his own administration, she added.
"Just because the president tweets something it does not mean that it is changing the foreign policy. That may sound strange, but that's where we are at in this new era of social media."
On Monday, Dana Shell Smith, US ambassador to Qatar, posted an embassy statement saying the "US supports Qatar's efforts in combating terrorism financing, and appreciates its role in coalition against ISIL".
US Secretary of State Rex Tillerson had also issued a statement encouraging the parties involved in the Gulf dispute to sit down and address their differences.
On May 21, Trump met with Qatar's Emir Sheikh Tamim Bin Hamad Al-Thani in Saudi Arabia.
During the meeting, Al Jazeera's Culhane reported, the US leader "bragged about how much military equipment the US sold" to Qatar.
"If you believe that they are the sole funder of extremism, it seems unlikely that you would want to supply them weapons," she said.
In 2015, the US sold an estimated $17bn worth of arms to Qatar, representing 42.5 percent of total US arms sales that year.
|On May 21, Trump met leaders of the Middle East and allies in Saudi Arabia [Reuters]|
Source: Al Jazeera News