Biden's order will likely shut off asylum requests and deny entrance to migrants once a daily threshold is exceeded, the sources said.

Biden, a Democrat seeking a second four-year term in the Nov. 5 election, has toughened his approach to border security in recent months as immigration has emerged as a top concern among voting-age Americans.

Republicans, including Biden's opponent, former President Donald Trump, have criticized the president for rolling back restrictive Trump-era border policies and failing to stem higher levels of illegal crossings.

The sources cautioned that Biden had yet to give a final approval to the plan. The announcement could come on Tuesday, the sources said.

A White House official said there had not been any final decisions regarding what additional executive actions, if any, could be taken.

Biden said in a Univision interview in April that he and his administration were trying to determine whether he has the authority to act on his own to shut down the U.S.'s southern border with Mexico to migrants, should it be deemed necessary.

An attempt at bipartisan migration legislation fell apart in February when Republicans blocked it. Biden blamed Trump for using his influence to derail the legislation to allow the Republican to maintain migration as an election issue.

"As we have said before, the administration continues to explore a series of policy options and we remain committed to taking action to address our broken immigration system," a White House spokesperson said.

The U.S. Border Patrol caught a monthly record of 250,000 migrants crossing illegally in December, but numbers have dropped significantly since then, with 137,000 arrests in March.