WASHINGTON -  US President Donald Trump fired all ambassadors to foreign countries and international organisations on his first day in office, with no concrete replacement envoys lined up, according to media reports.

Trump, who assumed power on January 20, had demanded that every ambassador in countries all over the world, who had been appointed by former President Barack Obama, leave their offices on the same day with no grace period.

As many as 80 ambassadors for countries, agencies and issues, including the ambassador for global women's issues, have been discarded.

According to common policy, politically-appointed ambassadors resign at the start of a new administration, but it is less common to have no replacements in line. Trump's transition team had announced the decision to foreign ambassadors on December 23.

The move risks cutting all direct connections of the US with Germany, the UK and Canada, as well as other critical allies. In addition, countries such as China, India, Japan and Saudi Arabia will be waiting for replacements, a lengthy process that is carried out by the US Congress.

So far, few appointments have been made, including South Carolina governor Nikki Hayley, who replaced Samantha Power as the US Ambassador to the United Nations. Haley was born as Nimrata Randhawa to Sikh parents, who migrated from Indian Punjab.

Also, bankruptcy lawyer David Friedman and Iowa Governor Terry Branstad have been appointed ambassadors to Israel and China respectively.

Trump has been under criticism for other major staffing gaps below cabinet level.

‘IF YOU'RE SO UPSET, WHY DIDN'T YOU VOTE’

President Donald Trump, in between tweets about his “long standing ovations” at CIA headquarters and his inauguration’s television ratings, implied in a tweet Sunday that the Women’s March protesters did not vote.

“Watched protests yesterday but was under the impression that we just had an election!” Mr Trump wrote. “Why didn’t these people vote? Celebs hurt cause badly.”

His tweet came in response to more than 1 million people gathering Saturday for the Women's March on Washington and at other rallies in the United States and abroad, all mean as a rejoinder to his inauguration a day before.

Trump and his aides remained silent about the protests on Saturday. In a separate tweet Sunday, Trump, who on Saturday accused the media of underreporting the crowd size at his swearing-in, boasted that the television ratings for his inaugural was higher than that of President Barack Obama's swearing in four years ago.

The massive event in Washington, which organisers said drew as many as half a million people, was packed with celebrities, including Madonna, Amy Schumer, America Ferrera and Ashley Judd.

"Wow, television ratings just out: 31 million people watched the inauguration, 11 million more than the very good ratings from four years ago!" Trump wrote.

Nielsen reported Saturday that 30.6 million viewers saw inaugural coverage between 10 am and 6 pm on Friday. That figure was lower than Obama's first inauguration in 2009, when 38 million viewers tuned in, according to Nielsen.

The record is held by Ronald Reagan, when 42 million watched his inaugural festivities in 1981. The Women's March — which was sponsored by Planned Parenthood and NARAL Pro-Choice America, among other groups — drew some criticism for bumping a sponsor with pro-life views.

The official's statement also blasted pop star Madonna, who spoke and performed at the march, for saying she "thought an awful lot about blowing up the White House" due to Trump’s presidency.

"Comments like these are absolutely unacceptable and had they been said about President Obama, the mainstream media would be in an uproar," the White House said. "The Trump administration welcomes a robust discussion regarding the critical issues facing America's women and families."

Initial reports said the statement was an official release from the White House. But White House Press Secretary Sean Spicer said on Twitter it was not an official White House statement.

AFP adds: Trump, facing unfavorable comparisons to the turnout for his inauguration a day earlier, launched a sharp attack on the news media, saying they lied about the numbers watching his swearing-in.

"It looked like a million, million and a half people," he said, adding that "all the way back to the Washington Monument was packed."

The Capitol, where Trump took the oath of office, is just over a mile from the monument.

White House press secretary Sean Spicer also lashed out at media that published photos demonstrating that the crowd was far from reaching the monument - calling their reporting "shameful."

Burned by past controversies over the size of demonstrations, US capital authorities no longer estimate crowd sizes.

Trump spokesmen appeared on the defensive Sunday when asked on television about the administration's preoccupation with crowd size.

When senior aide Kellyanne Conway was asked on NBC why Trump sent out his spokesman to convey a "provable falsehood" about the turnout, she replied that "Sean Spicer gave alternative facts."

That statement caused a huge response on Twitter, with mocking comments about #alternativefacts trending to the top in the US and to the second-highest spot worldwide.

Both Conway and Spicer sought on Sunday to shift the debate to the days ahead. They noted that the Republican president has a hectic schedule for the week, including plans to sign several executive orders to carry out campaign promises.