As lawmakers await a decision on whether the White House will back a bipartisan budget agreement to avert another government shutdown, President Trump insisted Wednesday his administration will construct a wall along the southwestern border regardless of congressional support.

"As we review the new proposal from Congress, I can promise you this: I will never waver from my sacred duty to defend this nation and its people," the president said during remarks to a conference of sheriffs and police chiefs in Washington. "We will get the job done. The wall is very very on its way."

Mr. Trump said his "big" and "strong" proposed wall will deter illegal immigration and drug smuggling. "They will be able to climb Mt. Everest a lot easier," he added.

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Earlier Wednesday, during a photo op with the president of Colombia, Mr. Trump told reporters he'll be looking for rhetorical "land mines" in the legislation. He accused Democrats of being "stingy" with border funding, though he maintains he has "options that most people don't understand" for building a southern border wall.

Democrats and Republicans reached a deal late Monday on legislation to fund the government past the Friday deadline. Lawmakers are expected to vote on the deal Thursday evening.

Mr. Trump tweeted on Tuesday he had reviewed the border funding agreement reached by the bipartisan group of congressional negotiators. An official familiar with the matter told CBS News he is "very likely" to sign the deal if it reaches his desk, even though Mr. Trump told reporters Tuesday, "I can't say I'm happy. I can't say I'm thrilled."

CBS News' chief Washington correspondent Major Garrett told "CBS This Morning" on Wednesday the president has been handed the "worst deal of all the ones ever put before him" because it contains the smallest dollar amount possible for border security funding.

In recent days and weeks, the president hasn't ruled out the possibility of a national emergency declaration if he doesn't get sufficient funding for his border wall in the legislation. The declaration would allow him to bypass Congress to find money to build the wall.

According to Garrett, all necessary legal work has been done by the Department of Justice and the White House counsel's office for an emergency declaration. This does not mean Mr. Trump will necessarily declare a national emergency, but Garrett said "it's more likely than not" that the president will do so.

The administration is satisfied with the legality of the maneuver, but a declaration, if it is used, could still be challenged in court or found to be legally problematic, Garrett reports. However, the administration believes it has done its due diligence, according to a senior administration official.

Emily Tillett and Kathryn Watson contributed to this report.