WASHINGTON — US President Donald Trump is expected to remove Department of Homeland Security chief Kirstjen Nielsen and is considering replacing chief of staff John Kelly, a source close to the White House said, while Melania Trump issued a statement calling for the dismissal of the deputy security national adviser over her handling of the first lady's trip to Africa.

Trump has been mulling removing Nielsen, a Kelly protege who became the secretary at Homeland Security when he left the job to become Trump's chief of staff, for a number of weeks, the source said.

The source cautioned that Trump could still change his mind, but said he has grown weary of her in his push to harden the US border with Mexico. Trump has not decided on a candidate to replace Nielsen, The Wall Street Journal reported.

"The secretary is honored to lead the men and women of DHS and is committed to implementing the president's security-focused agenda to protect Americans from all threats and will continue to do so," said Tyler Houlton, a DHS spokesman, in response to an ABC News report about the possible staff changes.

Trump is also considering replacing Kelly, a retired Marine Corps general and a supporter of Nielsen, with Vice-President Mike Pence's chief of staff, Nick Ayers, the source said.

Two presidential aides said the president was considering forcing out deputy national security adviser Mira Ricardel, but as of Tuesday afternoon, the adviser remained in her West Wing office.

Melania Trump's office took the extraordinary step of issuing a statement saying that Ricardel should be ousted. While first ladies historically have been known to pressure their husbands over official business, they do not typically issue statements.

"It is the position of the Office of the First Lady that she no longer deserves the honor of serving in this White House," Stephanie Grisham, the first lady's spokeswoman, said in a terse statement.

If they leave, Kelly and Nielsen would join a list of people fired by Trump or who have resigned since he took office in January 2017, including former secretary of state Rex Tillerson and former attorney general Jeff Sessions, who was removed by the president last week.

The first lady had complained that she was unhappy with how she was treated by Ricardel, a former Boeing Co executive who worked on the Trump presidential campaign and was picked by National Security Adviser John Bolton to be his deputy earlier this year, two other sources told Reuters.

The sources said that Melania Trump explicitly asked the president to oust Ricardel after their dealings over the Africa trip "didn't go well". One source said that Melania Trump felt that Ricardel tried to short-change the first lady when it came to government resources allocated to support her Africa tour.

Reuters