Trump admin updates: Trump says tariff letters to be sent to 'various countries' on Monday

House Majority Leader Steve Scalise cast some doubt on the possibility that Republicans will succeed on Wednesday in passing President Trump's sweeping tax cut and spending bill.

"We'll see some time later today if we can get that done," Scalise told reporters. "So we still have some more conversations with members. Obviously, members have gone through the changes that the Senate made, and you know, some of them take us a little bit backwards. Some of them are a little bit better."

Asked by ABC News whether he feels like Republicans are short of the votes needed for passage, Scalise acknowledged the bumpy road both in the past and ahead.

"We've still had a lot of members that had questions about the changes that the Senate made. That's to be expected," the Louisiana lawmaker said.

Scalise added that the Senate's changes still reflect "85%" of the House's original bill, though he acknowledged House Republicans "would like to do more."

GOP leadership is meeting with small groups of members who haven't locked in their support, Scalise said, and the president is also helping on that today by talking to individual members as the party's "best closer."

-ABC News' John Parkinson

The House convened at 9 a.m. ET on Wednesday to start consideration of the Trump megabill.

The rule vote, a procedural motion to advance the measure, will occur in the 11 a.m. ET hour. If the rule passes, there will be debate on the bill and final passage timing remains unclear.

Several Republican holdouts have already said they plan to oppose to procedural vote, including House Freedom Caucus chairman Andy Harris from Maryland and South Carolina Rep. Ralph Norman.

President Trump urged lawmakers to pass his megabill in a new social media post on Wednesday morning, saying that because of "GROWTH," it will be "one of the most successful pieces of legislation ever passed."

"THIS GROWTH has already begun at levels never seen before," Trump said in the post on his conservative social media platform, Truth Social.

Trump also touted his tariff policy and said that the U.S. "will make a fortune this year, more than any of our competitors, but only if the Big, Beautiful Bill is PASSED!"

"Republicans, don’t let the Radical Left Democrats push you around. We’ve got all the cards, and we are going to use them," Trump added in the post.

The House Rules Committee voted 7-6 to advance President Donald Trump's megabill early on Wednesday, sending the legislation to the floor for consideration.

Republican Reps. Ralph Norman and Chip Roy sided with Democrats in voting against the measure in committee, the body having met for nearly 12 hours.

The House will next debate the measure with the hopes of holding a vote by Independence Day.

The lower chamber will convene for legislative business at 9 a.m. Wednesday, with debate followed by floor action, first on the rule vote.

Several hardliners are expected to vote against the procedural motion to advance the legislation, which could potentially put the House at a standstill.

-ABC News' Lauren Peller and Alex Ederson