WASHINGTON (AP) — The Senate reached a deal on Saturday to skip witness testimony in the impeachment trial of former president Donald Trump.

The agreement averts a prolonged trial and sets up closing arguments from both sides on Saturday.

THIS IS A BREAKING NEWS UPDATE. AP’s earlier story follows below.

WASHINGTON (AP) — The Senate impeachment trial of Donald Trump was thrown into confusion Saturday as lawmakers voted to consider hearing witnesses, a step that could significantly extend the proceedings and delay a vote on whether the former president incited the deadly Capitol insurrection.

The last-minute fight over witnesses followed Friday night revelations from a Republican House lawmaker about a heated phone call on the day of the riot between Trump and House Minority Leader Kevin McCarthy that Democrats say establishes Trump’s indifference to the violence.

Leaders were considering an arrangement that would move the trial back toward a final vote, without live witnesses.

The proceedings came to an abrupt halt less than an hour after getting underway, with senators taken aback by the unexpected development huddling on the floor of the chamber while leaders spoke to clerks at the dais. Both Democrats and Republicans braced for the possibility of a drawn-out dispute over which, and how many, witnesses might suddenly factor into a trial that just hours earlier was heading to a swift vote and likely acquittal.

After roughly an hour of private discussions, the Senate was adjourned until afternoon.

Impeachment trials are rare, especially for a president, and the rules are negotiated for each one at the outset. For Trump’s trial, the agreement said if senators agreed to hear witnesses, votes to hear additional testimony would be allowed.

A prolonged trial could upend President Joe Biden’s legislative agenda in Congress. Biden has barely commented on the trial, coming in the first days of his new administration, and whether his predecessor should be convicted or acquitted. He was spending the weekend at the Camp David presidential retreat in Maryland.

Any delay in the verdict could grind the big COVID-19 rescue package and other priorities to a halt.

Meanwhile, Republican leader Mitch McConnell made clear that he will vote to acquit Trump, according to a person familiar with his thinking. Closely watched, the GOP leader’s view could influence others in his party.

While most Democrat are expected to convict the former president, acquittal already appeared likely in the chamber that is split 50-50 with Republicans. A two-thirds majority is required for conviction.

At issue at first on Saturday was whether to subpoena Rep. Jaime Herrera Beutler of Washington state, one of 10 Republicans to vote for Trump’s impeachment in the House. She said in a statement late Friday that Trump rebuffed a plea from McCarthy to call off the rioters. Democrats consider it key corroborating evidence that confirms the president’s “willful dereliction of duty and desertion of duty as commander in chief.”

An agreement was being negotiated that would end the standoff and avoid a prolonged trial. Under the pending deal, Herrera Beutler’s information would be entered into the record in exchange for Democrats dropping their planned deposition. That would allow the trial to resume Saturday with closing arguments and a vote on the verdict. No witnesses would be called under the deal.

Lead House impeachment manager Rep. Jamie Raskin of Maryland said that witnesses were necessary to determine Trump's role in inciting the riot. There were 55 senators who voted for his motion to consider witnesses, including Susan Collins of Maine, Lisa Murkowski of Alaska, Ben Sasse of Nebraska and Mitt Romney of Utah. Once they did, Lindsey Graham of South Carolina changed his vote to join them on the 55-45 vote.

Trump lawyers opposed calling witnesses, with attorney Michael van der Veen saying it would open the door to him calling as many as 100. He said the depositions could be done in his law office in Philadelphia, prompting laughter from senators.

“If you vote for witnesses,” Van der Veen said, crossing his arms and then then raising them in the air for emphasis, “do not handcuff me by limiting the number of witnesses that I can have.”

Senators meeting as the court of impeachment are restrained in taking up other business without consent of the Republican minority, which is unlikely. Rules require senators to be present for the proceedings and this past week almost no other major items have been considered as the trial was underway.

The outcome of the raw and emotional proceedings is expected to reflect a country divided over the former president and the future of his brand of politics. The verdict could influence not only Trump’s political future but that of the senators sworn to deliver impartial justice as jurors.

“What’s important about this trial is that it’s really aimed to some extent at Donald Trump, but it’s more aimed at some president we don’t even know 20 years from now,” said Sen. Angus King, the independent from Maine.

The nearly weeklong trial has delivered a grim and graphic narrative of the riot and its consequences in ways that senators, most of whom fled for their own safety that day, acknowledge they are still coming to grips with.

House prosecutors have argued that Trump's rallying cry to go to the Capitol and “fight like hell” for his presidency just as Congress was convening Jan. 6 to certify Biden’s election victory was part of an orchestrated pattern of violent rhetoric and false claims that unleashed the mob. Five people died, including a rioter who was shot and a police officer.

Trump's lawyers countered in a short three hours Friday that Trump's words were not intended to incite the violence and that impeachment is nothing but a “witch hunt” designed to prevent him from serving in office again.

Only by watching the graphic videos — rioters calling out menacingly for House Speaker Nancy Pelosi and Vice President Mike Pence, who was presiding over the vote tally — did senators say they began to understand just how perilously close the country came to chaos. Hundreds of rioters stormed into the building, taking over the Senate. Some engaged in hand-to-hand, bloody combat with police.

Many Republicans representing states where the former president remains popular doubt whether Trump was fully responsible or if impeachment is the appropriate response. Democrats appear all but united toward conviction.

Trump is the only president to be twice impeached and the first to face trial charges after leaving office.

Unlike last year’s impeachment trial of Trump in the Ukraine affair, a complicated charge of corruption and obstruction over his attempts to have the foreign ally dig up dirt on then-campaign rival Biden, this one brought an emotional punch over the unexpected vulnerability of the U.S. tradition of peaceful elections. The charge is singular, incitement of insurrection.

On Friday, Trump’s impeachment lawyers accused Democrats of waging a campaign of “hatred” against the former president as they wrapped up their defense.

His lawyers vigorously denied that Trump had incited the riot and they played out-of-context video clips showing Democrats, some of them senators now serving as jurors, also telling supporters to “fight," aiming to establish a parallel with Trump's overheated rhetoric.

“This is ordinary political rhetoric,” said van der Veen. “Countless politicians have spoken of fighting for our principles.”

Democratic senators shook their heads at what many called a false equivalency to their own fiery words. Impeachment managers say that Trump was the “inciter in chief” whose monthslong campaign against the election results was rooted in a “big lie” and laid the groundwork for the riot, a violent domestic attack on the Capitol unparalleled in history.

“Get real,” Raskin said at one point. “We know that this is what happened.”

Six Republican senators who joined Democrats in voting to take up the case are among those most watched for their votes.

Early signals came Friday during questions for the lawyers.

Sens. Susan Collins, R-Maine and Lisa Murkowski, R-Alaska, asked the first question, Two centrists known for independent streaks, they leaned into a point the prosecutors had made, asking exactly when Trump learned of the breach of the Capitol and what specific actions he took to end the rioting.

Democrats had argued that Trump did nothing as the mob rioted.

Another Republican who voted to launch the trial, Sen. Bill Cassidy of Louisiana, asked about Trump’s tweet criticizing Pence moments after the then-president was told by another senator that Pence had just been evacuated.

Van der Veen responded that at “no point” was the president informed of any danger. Cassidy told reporters later it was not a very good answer.