WASHINGTON — In a surprising move, Senate Majority Leader Mitch McConnell on Tuesday announced plans to bring a criminal justice reform bill to the Senate floor this month for a vote.

“At the request of the president and following improvements to the legislation that have been secured by several members, the Senate will take up the recently revised criminal justice bill this month," McConnell, a Kentucky Republican, said in remarks on the Senate floor. "I intend to turn to the new text as early as the end of this week."

This comes a day after the junior GOP senator from Kentucky, Rand Paul, called on McConnell to hold a vote on the legislation and urged people to put public pressure on the majority leader.

"I will tell you that we need the help of one person," Paul said. "The one person who had the power to allow this vote — and I'm not saying he's stopping it — but there is one person. He's from Louisville, he's fairly well known and he has the power to allow or disallow this vote.

"There's no reason we shouldn't vote. So I would say if you're in Louisville, call and say, 'Senator McConnell, all we want is a vote'. It will pass overwhelmingly."

Lawmakers have been working on overhauling the criminal justice system for the first two years of President Donald Trump's administration in coordination with White House officials. A bill called "The First Step Act" has the best chance of passing; it currently has 31 co-sponsors in the Senate, both Democrats and Republicans. The House version of the bill passed with overwhelming support in May.

"As a reminder, Speaker Ryan has said the House will be ready to act on the revised CJR bill," AshLee Strong, spokesman for House Speaker Paul Ryan, R-Wisc., said on Twitter Tuesday.

The legislation would implement the most sweeping set of reforms to the system since the 1990s by shortening some long prison sentences and improving conditions for people in prison, among other things.

Still, McConnell has been reluctant to bring up the bill even though he said before November's midterm elections that he would hold a vote if at least 60 senators supported the measure. McConnell was hesitant because his caucus was split on the original version of the proposal, which some Republicans saw as being lenient on some criminals, like drug traffickers.

It gained fierce opposition from Sen. Tom Cotton, R-Ark., who was actively urging other members to join him in opposition.

Cotton made it clear Tuesday that he's still opposed to the version that will receive a vote, telling NBC News, "I don't think the Senate should vote to let carjackers and bank robbers out of prison. Maybe other senators do, that's their prerogative. But I'll have a lot of amendments to offer."

McConnell said that changes in the bill, which had to do with sentencing leniency, is a reason why he’s bringing it to the floor. Because of those changes, a number of GOP senators announced their support, including Sen. David Perdue of Georgia.

Sen. Chuck Grassley, R-Iowa, told reporters Tuesday that about a third of the Senate supports the bill.

"I think that what we brought up is, we've done everything that people have asked us to to get support for this bill," Grassley said. "We increased the number of votes when McConnell asked me to have more than 60 votes six weeks ago. We've proceeded down that road to get more votes."

Trump tweeted over the weekend that he hopes McConnell will "go for it."

"It is extremely popular and has strong bipartisan support. It will also help a lot of people, save taxpayer dollars, and keep our communities safe. Go for it Mitch!" Trump said on Twitter.

McConnell also made clear in his remarks Tuesday that the Senate may have to stay in session between Christmas and New Year's, "as a result of this additional legislative business."

Congress has less than two weeks to address government funding and the president’s request for border wall money before next Friday's Dec. 21 deadline to avoid a shutdown.

House Republicans announced Tuesday that they are canceling the first two days in session next week, which means they only have five legislative days left to pass an appropriations package.