Washington (AP) ―House Speaker Mike Johnson on Monday unveiled a complicated proposal for passing wartime aid for Israel, Ukraine and Taiwan, leaving its path to passage deeply uncertain as he rejected pressure to simply approve a package sent over by the Senate.

The Republican speaker huddled with fellow GOP lawmakers Monday evening to lay out his strategy to gain House approval for the funding package. Facing an outright rebellion from conservatives fiercely opposed to aiding Ukraine, Johnson said he would push to get the package to the House floor under a single debate rule, then hold separate votes on aid for Ukraine, Israel, Taiwan and several foreign policy proposals, according to Republican lawmakers.

However, the package would deviate from the $95 billion aid package passed by the Senate in February, clouding its prospects for final passage in Congress.

Iran's missile and drone strike against Israel over the weekend put renewed pressure on House Republicans to act on the national security package after Johnson had spent the past two months mulling how to advance it through the political divides in the House.

As the House has struggled to act, conflicts around the globe have escalated. Israel’s military chief said Monday that his country will respond to Iran’s weekend missile strike. And Ukraine’s military head over the weekend warned that the battlefield situation in the country’s east has “significantly worsened in recent days,” as warming weather has allowed Russian forces to launch a fresh offensive.

Meanwhile, President Joe Biden, hosting Czech Prime Minister Petr Fiala at the White House, called on the House to take up the Senate funding package immediately. “They have to do it now,” he said.

In the Capitol, Johnson's approach could further incite the populist conservatives who are already angry at his direction as speaker.

Rep. Marjorie Taylor Greene, a Georgia Republican, is already threatening to push to oust him as speaker. As she entered the closed-door Republican meeting on Monday, she said her message to the speaker was, “Don’t fund Ukraine.”

The GOP meeting was filled with lawmakers at odds in their approach to Ukraine: Republican defense hawks, including the top lawmakers on national security committees, who want Johnson to finally take up the national security supplemental package as a bundle, are pitted against populist conservatives who are fiercely opposed to continued support for Kyiv’s fight at all.

Senior Republicans and Democrats were also growing impatient after Johnson had offered them assurances that he would bring Ukraine aid to the floor.

“The House must rush to Israel's aid as quickly as humanly possible, and the only way to do that is passing the Senate's supplemental ASAP," said Senate Majority Leader Chuck Schumer.

Meanwhile, the White House would oppose a standalone bill that only addressed aid for Israel, National Security Council spokesman John Kirby said. Democratic leaders are pressuring Johnson to take up the Senate-passed bill that would provide a total of $95 billion for the U.S. allies, as well as humanitarian support for civilians in Gaza and Ukraine.

House Democratic Leader Hakeem Jeffries pledged in a letter to lawmakers to do “everything in our legislative power to confront aggression" around the globe, and he cast the situation as similar to the lead-up to World War II.

“The gravely serious events of this past weekend in the Middle East and Eastern Europe underscore the need for Congress to act immediately,” Jeffries said. “We must take up the bipartisan and comprehensive national security bill passed by the Senate forthwith. This is a Churchill or Chamberlain moment.”

During a private meeting last week, two senior Democrats, Rep. Nancy Pelosi, the speaker emerita, and Rep. Steny Hoyer, the former No. 2 leader, encouraged their Democratic colleagues to sign on to a discharge petition that could force the House to vote on the Senate aid package.

Pelosi and Hoyer told the Democratic lawmakers that even if they oppose the bill, they could still sign the discharge petition to at least push the package to the floor -- and then vote against it later. The leaders’ message was confirmed by two people familiar with the private meeting and granted anonymity to discuss it.

So far, 195 lawmakers have signed on to the discharge petition, about a dozen shy of the majority needed to force action on the floor. Many of the progressive Democrats holding out from signing the petition are against U.S. aid to Israel due to the Netanyahu government’s assault on Gaza that has killed thousands of civilians.

On the right, the House Freedom Caucus said Monday that it opposed "using the emergency situation in Israel as a bogus justification to ram through Ukraine aid with no offset and no security for our own wide-open borders.”