WASHINGTON — President Donald Trump injected the United States into a volatile crisis among America’s Mideast allies, siding Tuesday with Saudi Arabia and other countries against Qatar in a dispute that threatens to disrupt efforts to defeat the Islamic State group and counter Iran.

In a series of early-morning tweets, Trump appeared to endorse the accusation that the small, gas-rich kingdom funds terrorist groups, a serious allegation against a strategic U.S. partner that hosts a base with some 10,000 American troops. He also sought to cast the anti-Qatar action led by the Saudis and the United Arab Emirates as the result of his trip last month to Riyadh, where he pressed leaders from dozens of Arab and Muslim governments, including Qatar’s emir, to combat extremism.

Trump said he’d told the kings, presidents and prime ministers that funding “Radical Ideology” can’t be tolerated, and “Leaders pointed to Qatar – look!”

“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!” Trump said on Twitter, claiming his visit to Saudi Arabia was “already paying off.”