 -- President Donald Trump, who is on a working vacation at his New Jersey estate, prodded Senate Majority Leader Mitch McConnell to "get back to work" in a tweet Thursday — the latest volley between the two men over the stalled Republican health care efforts.

"Mitch, get back to work and put Repeal & Replace, Tax Reform & Cuts and a great Infrastructure Bill on my desk for signing," wrote Trump, who is in the midst of a 17-day stay at his private golf club. "You can do it!"

In a press conference later in the day, a reporter asked Trump whether McConnell should step aside as majority leader. "Well, I'll tell you what, if he doesn't get repeal and replace done and if he doesn't get taxes done, meaning cuts and reform, and if he doesn't get a very easy one to get done, infrastructure, if he doesn't get them done, then you can ask me that question," Trump replied.

He added, "Let's hope he gets it done."

Trump later took another round of questions from reporters, saying he's "very disappointed" in McConnell.

Earlier Thursday, former Speaker of the House Newt Gingrich, a staunch ally of Trump's, defended McConnell against the president's criticism of Senate Republicans' failure to pass health care legislation. The Senate is currently in recess until after Labor Day.

Gingrich, who met recently with the president, said Trump bears some responsibility for Republicans' failure to deliver on their promise to repeal and replace Obamacare.

"The fact is with a very narrow margin — 52 people — Mitch McConnell got 49 out of 52. I think the president can't disassociate himself from this," Gingrich said in an interview on Fox News on Thursday morning. "[Trump] is part of the leadership team. He is not an observer sitting up in the stands. He is on the field. It was a collective failure."

Trump has been on a tear against McConnell since the failure of a series of Senate bills to replace or repeal the Affordable Care Act in late July. At a Rotary Club gathering in Kentucky on Monday, McConnell bemoaned what he called the president's "excessive expectations" and said Trump's pressure to move quickly on the party's agenda was behind the public's perception that Republicans haven't accomplished much, despite controlling Congress and the White House.

Trump tweeted Thursday morning that McConnell has "screamed" for seven years about the need to repeal and replace the ACA but "couldn't get it done."

The tweet continued a theme Trump began Wednesday when he questioned why Republicans haven't been able to repeal and replace Obamacare — an effort that began soon after the law was passed in 2010.

"Part of the reason, I think, that the story line is that we haven't done much is because, in part, the president and others have set these early timelines about things need to be done by a certain point," McConnell said Monday.

He suggested that Trump's lack of government experience contributed to his high hopes.

"Our new president, of course, has not been in this line of work before. And I think he had excessive expectations about how quickly things happen in the democratic process," said McConnell. "So part of the reason, I think, people feel we're underperforming is because too many artificial deadlines — unrelated to the reality of the complexity of legislating — may not have been fully understood."

The most recent congressional Republican health care reform effort was dealt a serious setback on July 27, when legislation to simply repeal the Affordable Care Act was defeated in the Senate, 49-51. Three of the chamber's Republicans voted against the bill. Trump has since called for Republicans to continue their attempts, though any work on the matter will have to wait until Congress returns from its August recess.

ABC News' Ali Rogin contributed to this report.