The new president posted on his Truth Social media network that he would fire more than 1000 presidential appointees “who are not aligned with our vision,” including some high-profile names.

Trump dismissed chef and humanitarian Jose Andres from the President’s Council on Sports, Fitness and Nutrition, retired general Mark Milley from the National Infrastructure Advisory Council, former State Department official Brian Hook from the board of the Wilson Centre, and former Atlanta mayor Keisha Lance Bottoms from the President’s Export Council.

“YOUR’E FIRED!” he wrote in a post just after midnight Tuesday.

Milley, the former chairman of the joint chiefs of staff under Trump, received a pardon from former president Joe Biden over concerns he could be criminally targeted by the new administration.

His portrait in the Pentagon was also removed. Hook, who was Trump’s Iran envoy during his first term, had been involved in the Trump administration transition. No reasoning was given for his firing.

Biden also removed many Trump appointees in his first days in office, including former press secretary Sean Spicer from the board overseeing the US Naval Academy.

Trump was set to continue building on his barrage of inauguration day announcements with plans to announce a new partnership to invest in artificial intelligence.

Three major business leaders — SoftBank Group CEO Masayoshi Son, OpenAI CEO Sam Altman and Oracle Corporation chairman Larry Ellison — were scheduled to join Trump in the afternoon to announce the creation of a new company called Stargate, which would invest up to $US500 billion ($797.6 billion) over the next four years in AI infrastructure, according to the White House.

Stargate intends to start building the project in Texas.

Trump also attended a national prayer service at Washington National Cathedral, a customary visit for new presidents and one that will wrap up his four days of inauguration-related events.

One of the speakers at the interfaith service, the Right Reverend Mariann Budde, the Episcopal bishop of Washington, used her sermon to send a message to Trump, urging compassion for LGBTQ+ people and undocumented migrant workers.

“You have felt the providential hand of a loving God. In the name of our God, I ask you to have mercy on the people in our country who are scared now,” said Budde, who has criticised Trump before.

Asked afterward by a reporter what he thought of the service, Trump said: “Not too exciting was it. I didn’t think it was a good service. They could do much better.”

Later in the day, the president was expected to meet with House Speaker Mike Johnson and Senate Majority Leader John Thune and other GOP legislators. It’s the first formal sit-down for the GOP leadership teams, including House Majority Leader Steve Scalise, Senate GOP Whip John Barrasso and the new president, as they chart priorities for using Republican power in Washington.

Despite an ambitious 100-day agenda, the Republican-led Congress is not on the same page on some ideas and strategies as they rush to deliver tax cuts for the wealthy, mass deportations and other goals for Trump.

Trump used the first hours of his presidency on Monday to sign a series of executive orders and memorandums, moving quickly to show that his new hold on the US government would be a stark change from his predecessor.

He pardoned hundreds of people for their roles in the January 6, 2021, attack on the US Capitol, withdrew the US from the Paris climate accords and the World Health Organisation, began his immigration crackdown by declaring a national emergency at the US-Mexico border and sought to end automatic citizenship for anyone born in America, which is expected to run into constitutional challenges.

He also signed an order that intends to pause a ban on TikTok for 75 days to give its China-based parent company more time to find an approved buyer.