Image copyright Getty Images Image caption From left: McConnell, Trump and Ryan

US President Donald Trump has ratcheted up a bitter feud with the leadership of his own party, blaming them for a legislative "mess".

The Republican president blamed Mitch McConnell for failing to pass measures on the US debt limit and healthcare.

It came a day after Mr McConnell, the Senate majority leader, played down reports of a rift.

Conservatives fear any tensions could imperil a big-ticket item in the Republican in-tray: tax reform.

The party's ability to govern is under scrutiny after a patchy legislative record this year despite its control of the White House, Senate and House of Representatives.

In Thursday morning's tweets, Mr Trump claimed that Mr McConnell and House Speaker Paul Ryan had failed to heed his advice to insert a debt ceiling measure into a veterans' bill which the president signed into law this week.

"Could have been so easy-now a mess!" he said.

Minutes later, Mr Trump targeted the Senate leader again, faulting him for last month's failure to overturn Obamacare.

"The only problem I have with Mitch McConnell is that, after hearing Repeal & Replace for 7 years, he failed! That should NEVER have happened!"

Why Trump's supporters will never leave him

By Katty Kay, Presenter, BBC World News

Jerry, I'll call him that, is a mild-mannered African American in his early 70s from West Virginia.

He grew up under segregation and it was to his family's deep dismay that he voted for Mr Trump last year.

He believes Mr Trump understands that America needs more discipline: no more young men walking round with their jeans halfway down their butts showing off their boxers, was how he described it to me.

Jerry hankers for a time when young men dressed well, behaved well and didn't answer back to their elders.

When I asked him if he'd be disappointed if Mr Trump failed to live up to his campaign promises of healthcare reform, tax reform and making American manufacturing great again, Jerry was clear.

Mr Trump, he said, would probably never achieve any of those things for three reasons - the media, the Russia investigation and the Republican Party.

Read Katty's take

Mr McConnell, who was addressing a group of Kentucky farmers on Thursday, offered muted criticism of Mr Trump.

He said he was "a little concerned about some of the trade rhetoric" by the president.

The Senate leader added: "The assumption that every free trade agreement is a loser for America is largely untrue."

A fiscal crisis is looming if Congress does not raise the US debt limit by the end of September.

At the same time, a separate budget battle is expected to unfold as lawmakers attempt to pass a massive government spending bill.

Mr Trump's latest tweets came a day after he issued a plea for unity and healing during a speech in Nevada.

The New York Times reported this week that Mr McConnell had doubts about Mr Trump's ability to save his presidency.

Media playback is unsupported on your device Media caption One came to applaud Trump, the other to boo

On 9 August, the two men engaged in a "profane shouting match" during a phone call, the newspaper also reported.

Mr McConnell and Mr Trump went into damage-limitation mode on Wednesday, playing down the claims.

The Kentucky senator said in a statement he and President Trump were "committed to advancing our shared agenda together".

The White House said the two would "remain united".

Mr McConnell riled Mr Trump earlier this month when he said the president had "excessive expectations about how quickly things happen in the democratic process".

Mr Trump told a crowd in Phoenix, Arizona, on Tuesday he would shut down the government if Congress does not grant the funding to build a wall on the US-Mexico border.

But eight votes from Democrats, who oppose a new border wall, are required for the debt ceiling bill to pass.