WASHINGTON (TNND) — Tuesday marks President Donald Trump's first full day in office and similar to Inauguration Day, the president and his team are moving quickly to make change.

At 4 p.m. EST, Trump is expected to make a "massive announcement" on infrastructure, the White House says. Press Secretary Karoline Leavitt told Fox News it would "send a message to the world," while declining to detail the news.

Earlier in the day, President Trump attended a national prayer service at Washington National Cathedral with Vice President JD Vance and family. The visit, a tradition for new presidents, was one of his last inauguration-related events.

Trump is also expected to meet with a bicameral group of congressional leaders Tuesday afternoon, including House Speaker Mike Johnson, R-La., and Senator Majority Leader John Thune, R-S.D.

In the early hours of Tuesday morning, Trump shared on Truth Social that he is firing over 1,000 presidential appointees from the Biden Administration, including retired Gen. Mark Milley of the National Infrastructure Advisory Council. Milley received a pardon from former President Joe Biden on Monday alongside Biden family members and other key administration figures.

Following his swearing-in ceremony Monday, Trump spent his first hours in office signing executive orders on topics including immigration, withdrawing from the Paris Climate Accords and World Health Organization and pardoning January 6 rioters.