Trump attacks McConnell and Ryan amid debt ceiling fight

— -- President Trump is again taking aim at Republican leaders, with looming legislative fights on the debt ceiling and potential shutdown of the federal government, blasting House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell, the target of a number of Trump's recent barbs, as having failed on key issues.

In a pair of tweets Thursday morning, Trump attacked McConnell and Ryan for not tying an increase in the debt limit to a recent Veterans Affairs bill that passed Congress with overwhelming bipartisan support.

It's unlikely, however, that Trump's proposal would have succeeded on Capitol Hill.

Historically, Republicans and Democrats have clashed over how to raise the debt ceiling and are motivated by the threat of default. Linking a popular VA reform bill to the must-pass legislation likely would have only delayed the passage of the former and not expedited the passage of the latter.

Trump's attack on McConnell is just the latest in what has devolved into a bitter feud between the president and the top Senate Republican.

An aide to McConnell told ABC News that McConnell and Trump have not spoken since a phone call on Aug. 9, in which Trump attacked McConnell over the failed votes on repealing Obamacare and for not effectively protecting the president in the face of mounting inquiries into his campaign's alleged ties to Russia.

The public spat resulted in the White House and McConnell issuing separate statements Wednesday assuring the public that the two still have shared legislative priorities and will hold previously arranged meetings upon Congress' return from the August recess.

McConnell and Ryan have backed away from Trump's threat on Tuesday at a raucous Phoenix rally that he is willing to shut down the government if Congress fails to secure funding for his promised wall on the U.S.-Mexico border .

"I don't think a government shutdown is necessary, and I don't think most people want to see a government shutdown," Ryan said in a brief press conference after a tour of an Intel facility in Oregon.

ABC's Benjamin Siegel contributed to this report.