Trump 2nd term: ICE arrests 956 undocumented immigrants on Sunday

The White House has released an official schedule for Trump's fourth day in office.

At 11 a.m. ET he will deliver remarks virtually to the World Economic Forum and have a panel discussion with global CEOS.

At 2:30 p.m. ET, he will have an "executive order signing" in the Oval Office. It's not immediately clear what action he will be taking.

Later, at 3:30 p.m. ET, he will hold a call with El Savador's President Nayib Bukele.

Lee Zeldin's nomination to lead the Environmental Protection Agency has been advanced in an 11-8 vote by the Senate Environment and Public Works Committee.

Zeldin, a former congressman, emphasized accountability during his confirmation hearing.

He also said he'd potentially "claw back" funds dispersed under the Inflation Reduction Act, one of former President Joe Biden's biggest legislative accomplishments. The law provides billions for renewable energy and combatting climate change.

The Senate will vote today on John Ratcliffe's nomination to serve as director of the CIA.

If senators approve his nomination, he will be the second member of Trump's team to be confirmed after Marco Rubio was sworn in as secretary of state earlier this week.

Later this afternoon, the Senate will take a procedural vote on Pete Hegseth's nomination to serve as defense secretary. Only 50 votes will be needed to advance his nomination. If he gets the votes, a final confirmation vote could occur on Friday or early Saturday.

Hegseth's nomination was advanced out of a Senate committee earlier this week on a party-line vote. New allegations have surfaced since then alleging abusive behavior, which his attorney has denied.

-ABC News' Allison Pecorin

Trump's executive order challenging birthright citizenship will face its first legal test in a Seattle courtroom on Thursday.

A federal judge will hear a request made by four Democratic-led states to issue a temporary restraining order against the executive order signed by Trump on Day 1 that purports to limit birthright citizenship to people who have at least one parent who is a United States citizen or permanent resident.

Read more about the case here.

-ABC News' Peter Charalambous and Laura Romero