WASHINGTON — Senate Democrats plan to submit a counteroffer in response to a plan put forward by Republicans Tuesday that would reopen the Department of Homeland Security following a shutdown that has lasted more than five weeks.

GOP lawmakers had tentatively agreed to move on a bill that would fund all the department’s functions outside of immigration enforcement and removal following a meeting with President Trump on Monday night, a source familiar with discussions told The Post.

But Senate Minority Leader Chuck Schumer (D-NY) signaled Tuesday that a major sticking point needs to be addressed before Democrats can support the measure. 

“This does not have any reforms to ICE, but negotiations are ongoing,” Schumer told reporters on Capitol Hill. “They sent us an offer and we’ll send an offer back.” 

The Democratic leader added, “Every one of my colleagues, every one, A.) believes we should be unified, and, B.) we need reforms of ICE — every single one.”

Schumer didn’t go into detail about the specific reforms he wants to tack on to the GOP proposal, simply stating, “We have to rein in ICE and stop the violence.” 

Senate Majority Leader John Thune (R-SD) argued that since Immigration and Customs Enforcement (ICE) isn’t being funded as part of the proposed deal, additional reform measures shouldn’t be included. 

“A lot of the reforms are contingent on funding for ICE,” Thune said, according to Axios. “If you’re not going to have funding, I don’t know how all of a sudden now you can demand reforms.”

Democrats had been hoping for reforms to ICE operations, including requiring agents to go maskless, show identification and obtain judicial warrants for arrests inside homes and businesses.

Universal body cameras for ICE officers was a concession that border czar Tom Homan noted was already being implemented, downplaying the need for Congress to force the agency into the practice.

“The Democrats have basically gave up on the reforms. And they’ve given up on that a long time ago. I never thought that was serious,” Thune said in a swipe at Schumer. 

One insider still argued, “Everything is still fluid.”

A spokesman for Thune, Ryan Wrasse, noted late Tuesday night that Senate Democrats had yet to submit a counteroffer. 

Wrasse asserted that the proposal on the table “includes all of the bipartisan proposals that were included in the deal Dems walked away from in January,” such as funding for body cameras and additional training. 

“Demanding additional reforms to portions of the bill you’re insisting be removed is a non-starter, and it doesn’t make sense,” he argued. 

But even Republicans don’t seem to be fully on board with the deal as is. 

“I can’t imagine why we’re doing something where everybody in federal government is not getting paid while senators get paid,” Sen. Rick Scott (R-Fla.) told Axios.

Nonetheless, the White House appears to be supportive. 

“Conversations are ongoing,” a White House official said Tuesday, “but this deal seems to be acceptable.”

President Trump complicated matters further during remarks in the Oval Office during a swearing-in ceremony for former Sen. Markwayne Mullin (R-Okla.) to serve as the next Homeland Security secretary.

“They’re negotiating a deal. I guess they’re getting fairly close, but I think any deal they make, I’m pretty much not happy with it,” Trump said. 

“These guys came in, they wouldn’t pay people, you know, they had a deal to pay. They had to break their deal. The Democrats broke the deal that we had. It was all done.”

Thune didn’t immediately comment on the president’s response but told reporters that “the offer originated with the Democrats, and that is to fund 94% of the DHS budget.”

The breakthrough could end weeks of chaos at America’s airports due to Transportation Security Administration employees, who are paid by DHS, missing paychecks and skipping work.

Thune said that $5.5 billion for ICE enforcement already tucked into Trump’s One Big Beautiful Bill last year “would not be included,” nor would reforms Democrats have been requesting to DHS be included.

Senate Democrats had held up funding in protest of ICE and its division of Enforcement and Removal Operations carrying out Trump’s “mass deportations” — but with the separation of that spending from other DHS agencies, Thune noted their party won’t be able to “demand reforms.”

Follow The Post’s live coverage of President Trump and national politics for the latest news and analysis

New urgency was given to the talks when a Canadian passenger plane collided with a fire truck on the runway of LaGuardia Airport late Sunday, killing both pilots and injuring more than 40 others.

Monday night, Sens. Katie Britt (R-Ala.) and Patty Murray (D-Wash.), the party’s top appropriator in the Senate, huddled on the upper chamber’s floor following an Oval Office meeting with the president to discuss a compromise.

While some details need to be ironed out, the preliminary provisions would fund Immigration and Customs Enforcement and its subagencies dealing with deportations as part of a separate budget reconciliation bill.

Sen. John Kennedy (R-La.) was among those calling for Thune to follow this path late last week when talks between the GOP and Democrats reached an impasse.

“Sen. [Ted] Cruz [R-Texas] and I a few days ago came up with a two-step process,” Kennedy told Fox News’ “America’s Newsroom” on Tuesday. “Step one: We would open up everything at DHS except ICE, including TSA, which the Democrats have already agreed to.

“And then we would fund ICE through reconciliation, which we could do only with Republican votes. We wouldn’t need any Democratic votes,” he added. “I talked to Sen. Thune last night and he says the president has reconsidered and may be on board.”

The DHS shutdown stretched into its 38th day on Tuesday — after Trump indicated over the weekend that no funding bill would clear his desk without approval of a bill beefing up voter ID requirements for Americans via another piece of legislation known as the SAVE America Act.

Thune suggested that the bill could be added to the second reconciliation measure that the Senate could begin deliberating the week after Easter break.

The shift comes as Mullin prepares to take over as DHS secretary next month after being confirmed by the Senate Monday night.

In a 54-45 vote, the former senator from Oklahoma was confirmed to take over DHS following the March 5 firing of Homeland Security Secretary Kristi Noem.

Noem’s mishandling of two fatal January shootings of American citizens by ICE and Customs and Border Protection officers in Minnesota had drawn sharp criticism from Democrats and even some Republicans.

Other Senate Republicans also called out her massive nine-figure spending on an ad campaign — starring herself — that she claimed the president personally authorized.

Trump denied having approved the $220 million promotional blitz and announced Noem’s departure from DHS for a role at the State Department.