The Senate blocked President Trump from being able to make recess appointments on Thursday as lawmakers leave Washington for their August break.

Sen. Lisa Murkowski (R-Alaska), doing wrap up for the entire Senate, locked in nine "pro-forma" sessions - brief meetings that normally last roughly a minute.

The move, which requires the agreement of every senator, means the Senate will be in session every three business days throughout the August recess.

The Senate left D.C. on Thursday evening with most lawmakers not expected to return to Washington until after Labor Day.

Senators were scheduled to be in town through next week, but staffers and senators predicted they would wrap up a few remaining agenda items and leave Washington early.

Trump isn't the first president to face the procedural roadblock from Congress.

The Senate has used the brief sessions to block recess appointments for decades, including last year to keep President Barack Obama from being able to fill a vacant Supreme Court seat.

But the current deal comes after Trump repeatedly lashed out at Attorney General Jeff Sessions, sparking speculation that he would fire the former senator and try to name his successor while Congress was out of town.

Senate Minority Leader Charles Schumer (D-N.Y.) warned last month that Democrats had "tools in our toolbox" to block a recess appointment.

"We're ready to use every single one of them, any time, day or night. It's so vital to the future of the republic," he said.

A spokesman for Senate Majority Leader Mitch McConnell (R-Ky.) said late last month that he didn't have any announcements on pro-forma sessions, but he noted that "if the Senate doesn't adjourn, typically pro forma sessions happen every three days."

The spokesman added on Friday that the Senate was holding the brief sessions because they didn't get a deal on adjourning, not specifically to block the president from making recess appointments.

"So to meet our constitutional requirement of meeting every few days, we're doing pro formas. We didn't do it to block Trump," the aide said.

Under Article One of the Constitution "neither House, during the session of Congress, shall, without the consent of the other, adjourn for more than three days." The House is also currently holding pro-forma sessions.

Sen. Christopher Coons (D-Del.) added earlier Thursday that he expected the Senate would set up the pro-forma sessions, which require a GOP senator to briefly preside over the upper chamber.

"My understanding is that we will only recess for three days at a time. ...When we were in the majority I had to come down from Delaware and preside," he said.

Trump also needs to find a new secretary of Homeland Security after he named John Kelly his new chief of staff.

The GOP-controlled Senate also held pro-forma sessions over the week-long Fourth of July recess.

And Democrats held pro-forma sessions every three days in 2012 when Obama tried to appoint National Labor Relations Board members. The Supreme Court ruled in 2014 that he overstepped his constitutional authority.

Asked if he was now glad the NLRB case had been litigated, Coons added on Thursday to laughter: "I think it's important that there be restraints on the recess appointments."