U.S. President Donald Trump on Wednesday aligned himself solidly with conservative Republicans on immigration, criticizing a proposed bipartisan deal as "horrible" on border security and "very, very weak" on reforms for the legal immigration system.

The Senate proposal — aimed at addressing Democrats' demands for protections for young adults dubbed "Dreamers" brought to the United States illegally as children — fell far short of what most Republicans believe needs to happen, Trump told Reuters in an interview.

"It's the opposite of what I campaigned for," Trump said.

Many Democrats have said they will not vote for the bill without an immigration deal, and Republicans will need at least some Democratic votes to pass the funding extension in the Senate.

Trump said he thinks a deal on immigration is still possible. "Time is running out," he said.

Trump also said a federal government shutdown "could happen" by the end of the week, insisting that Democrats would be blamed if that happened. Trump did not rule out signing a short-term spending measure by a Friday deadline to prevent a shutdown.

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