President Donald Trump at a cabinet meeting Thursday urged Congress to find a quick resolution to the Department of Homeland Security shutdown that’s leading to increasing headaches for air travelers.

“They need to end the shutdown immediately, or we’ll have to take some very drastic measures,” Trump said from the White House.

He didn’t describe what measures he would take or detail his role in negotiations to resume funding DHS.

The DHS shutdown has dragged on for more than a month and has disrupted air travel. Transportation Security Administration agents are going without pay and are missing work in large numbers, leading to long lines at airports and increased pressure on lawmakers to find a deal, though they appear to be at an impasse.

Senate Majority Leader John Thune, R-S.D., told reporters on Thursday that Democrats were in receipt of Republicans’ “last and final offer,” according to MS NOW. Thune declined to provide details of the latest offer, but said the White House had “been involved on the back and forth that has occurred overnight.”

A group of Senate Republicans met with Trump at the White House of Monday and came out with what they heralded as a compromise proposal: funding for 94% of DHS, except for the enforcement and removal arm of Immigration and Customs Enforcement.

But Democrats — who have withheld their support for funding the agency since February, not long after federal agents killed two U.S. citizens in Minneapolis during an immigration crackdown — dismissed the proposal because it did not contain the ICE operational changes they had long sought. Those changes include requiring immigration agents to acquire judicial warrants before entering private property and banning the use of masks.

Republicans roundly rejected a Senate Democratic counteroffer on Wednesday that included some of those proposals.

In addition to extending the shutdown, the negotiations standoff raises the specter of cutting into a scheduled two-week recess that was supposed to begin at the end of this week. Thune told reporters Wednesday that it was an “open-question” whether lawmakers would be able to leave town as planned.

The White House signaled on background earlier this week that it was on board with the GOP plan to reopen DHS, but Trump has so far not publicly thrown his weight behind the proposal.

Earlier this week, the Trump administration sent ICE agents to airports to assist TSA. Trump on Wednesday suggested he may also deploy National Guard members to airports for additional help.

— Emily Wilkins contributed to this story.