The White House said Thursday that President Donald Trump supports a short-term spending bill to avert a government shutdown, as eroding support for the measure among Senate Democrats and some Republicans increased the prospects of a closure.

"The President supports the continuing resolution introduced in the House," deputy White House press secretary Raj Shah said in a statement.

"Congress needs to do its job and provide full funding of our troops and military with a two year budget caps deal. However, as the deal is negotiated, the President wants to ensure our military and national security are funded. He will not let it be held hostage by Democrats," Shah wrote.

The short-term spending bill would keep the government open through Feb. 16 while extending a children's health insurance program, and rolling back several taxes in the Affordable Care Act. House Republicans hoped to hold a vote as soon as Thursday, and Speaker Paul Ryan, R-Wis., expressed confidence it would pass.

Yet even if the House manages to approve the bill, its fate in the Senate was unclear.

Sens. Tim Kaine, D-Va., Mark Warner, D-Va., and Angus King, I-Maine, all of whom voted for the last short-term spending bill, said they would oppose the current GOP proposal. Republican Sen. Mike Rounds, S.D., joined Sen. Lindsey Graham, R-S.C., in saying he would vote no.

Senate Majority Leader Mitch McConnell, R-Ky., who blamed Democrats on Thursday for working to "manufacture a crisis," said colleagues should plan to work through the weekend if circumstances do not change. He urged Republicans to hold firm in their support for the bill.

"Joining Democrats to shut down the government plays right into the Democrats' hand. We are strongest when we stick together - that will produce the best spending deal and the best DACA deal - one that has a chance of being enacted into law," he wrote in a note to Republicans.

GOP lawmakers had tried to make sense of Trump's early-morning tweets, which seemed to directly contradict the legislative strategy of congressional Republicans by calling for the separation of a long-term extension of the popular Children's Health Insurance Program (CHIP) from a short-term spending bill to keep the government open through mid-February.

While Republicans like Ryan suggested that the president was endorsing the GOP's approach, others found the tweets inexplicable and unhelpful ahead of a possible election-year shutdown.

"We don't have a reliable partner at the White House to negotiate with," said Graham, entering the Capitol building on Thursday morning.

"This has turned into an s-show for no good reason, and the only way out of this thing is to grow up a little bit - and I think that's going to happen," he said.

The back-and-forth was reminiscent of the chaos that erupted last week after Trump tweeted criticism of an intelligence bill that his administration had endorsed the day before.

Republicans' goal is to force Democrats into the uncomfortable position of choosing between funding CHIP and their effort to win legal protections for hundreds of thousands of young undocumented immigrants known as "dreamers."

Senate Minority Leader Charles E. Schumer, D-N.Y., warned Thursday morning that "it doesn't look good" for the version of the stopgap set for a House vote and complained about the confusion resulting from Trump's tweets.

"We barely know who to negotiate with. ... They point at each other and nothing gets done," he said.

Some Republican aides said Trump was trying to be helpful when he posted his comments on Thursday morning.

"I think people are misreading this," tweeted Brett Horton, chief of staff to House Majority Whip Steve Scalise, R-La. "The president wants a long-term reauthorization [solution] for CHIP, and this CR does exactly that."

To senior Senate Republicans, however, Trump's intention was unclear.

Sen. Orrin Hatch, Utah - one of CHIP's founders - sought clarification from the White House on Thursday morning, and Senate Majority Whip John Cornyn, R-Texas, suggested Trump was confused.

"I don't know whether it's clear to the president that what we're trying to do is reauthorize CHIP long term, not just 30 days. I would understand his concern about doing it just 30 days, but we're trying to do a long term extension for CHIP," Cornyn said.

The GOP was prepared to target Democrats for opposing the short-term spending with the six-year extension of the children's health program. The attack would involve letters from governors and statistics from individual states, according to a senior aide.

"It's just confusing. I don't know what he means. I don't know why he's doing that," this person said about Trump's tweets.

In several tweets before 9 a.m., Trump blamed Democrats for a possible shutdown and argued CHIP should be "part of a long term solution, not a 30 Day, or short term, extension!" Later in the morning, he again raised the specter of a shutdown.

"If the country shuts down, which could very well be ... the worst thing is what happens to our military," Trump told reporters during a visit to the Pentagon.

If the government closes and its employees are furloughed, it will be the first time under unified party control of Congress and the White House. The military would not cease to operate, but troops would not be paid unless Congress specifically provided for it.

Early Thursday, some Republicans signaled that their patience with the president was wearing thin.

Rep. Charlie Dent, R-Pa., said that the level of support in the House for the short-term bill is unclear and that extending CHIP would help avoid a shutdown.

"A lot of House Republicans want a six-year extension. It's important to us," he said. "That's just another one of those inexplicable tweets that's not very helpful."

Another Republican, Rep. Mark Sanford of South Carolina, said he was uncertain how he would vote on the bill.

"It seems to be a work in progress. No one has completely pinned down what's coming next," he said.

Told of Trump's tweets, Sanford said: "It's fluid, topsy-turvy, whichever you prefer."

The last shutdown occurred in 2013 and lasted 16 days as Republicans tried unsuccessfully to force changes to the Affordable Care Act.

Shuttered national parks and monuments have become a symbol of shutdowns past, and the Trump administration is drawing up plans to keep them open despite the closure as a way to blunt public anger.