President Donald Trump angrily lashed out at unnamed Republican lawmakers on Sunday, saying they should “protect” him as repayment for his 2016 election coattails.

“It’s very sad that Republicans, even some that were carried over the line on my back, do very little to protect their President,” Trump tweeted at 4:14 p.m., EDT. That was just over an hour after he arrived back at the White House after spending around four hours at Trump National Golf Club in nearby Sterling, Virginia.

It’s very sad that Republicans, even some that were carried over the line on my back, do very little to protect their President. — Donald J. Trump (@realDonaldTrump) July 23, 2017

The eyebrow-raising tweet comes amid the ongoing scandal and multiple federal and congressional probes of Russia’s 2016 election meddling, including whether Trump’s campaign and the Kremlin colluded to undermine Democratic nominee Hillary Clinton. Republican lawmakers are increasingly voicing their views that the president should stop tweeting about the matter, especially during the Justice Department investigation being led by former FBI Director Robert S. Mueller.

By launching a public attack on his fellow Republicans, Trump could open the door to an all-out revolt among some members of his own party. While some Democrats talk about possible impeachment proceedings over the Russia allegations, legal and political experts agree that is unlikely as long as the president has the support of Republican leaders and rank-and-file members, who control both the House and Senate.