Prince Harry and his wife Meghan Markle, Absent from State Banquet to Honor President Trump

London (dpa) - US President Donald Trump and his family enjoyed a royal banquet hosted by Queen Elizabeth II at London's Buckingham Palace late Monday, ahead of large protests against his three-day visit expected on Tuesday.

"The Queen and the entire Royal Family have been fantastic," Trump tweeted after meeting the British monarch and most senior royals during a formal welcome ceremony and a private lunch at the palace earlier in the day.

Prince Charles, the Queen's eldest son and heir to the throne, and his wife Camilla, the duchess of Cornwall, hosted Trump and his wife Melania for tea on Monday afternoon.

Trump's daughter Ivanka and son-in-law Jared Kushner, his sons Eric and Donald Junior, and his daughter Tiffany were all among the 171 guests at the banquet.

"Tonight we celebrate an alliance that has helped to ensure the safety and prosperity of both our peoples for decades, and which I believe will endure for many years to come," the queen said in her speech at the banquet.

She proposed a toast "to President and Mrs Trump, to the continued friendship between our two nations, and to the health, prosperity and happiness of the people of the United States," the Royal Family said.

Prince Harry, the Queen's grandson and second son of Charles, and his wife Meghan, the Duchess of Sussex, were notable absentees from the banquet.

Former US actress Meghan was reportedly unable to attend royal engagements this week because she is still nursing the couple's three-week-old son Archie.

Harry did attend events at the palace earlier Monday.

Meghan had criticized Trump ahead of his election in 2016, calling him "misogynistic" and divisive during a US television interview.

Scores of protesters, led by women's groups, held a rival "people's banquet" in nearby Parliament Square while Trump enjoyed the royal banquet. Hundreds of others gathered outside the palace.

A much larger Together Against Trump march through central London is expected to attract thousands of protesters on Tuesday, when Trump is scheduled to meet British Prime Minister Theresa May and US and British business leaders.

Trump's arrival in London was overshadowed by his tweets insulting Sadiq Khan, London's first Muslim mayor.

Trump, who has had previous Twitter feuds with Khan, called him "a stone cold loser who should focus on crime in London, not me."

Khan had given several interviews to British media ahead of the visit, writing in Sunday's Observer newspaper that it was "un-British to roll out the red carpet" for Trump.

The visit comes as Britain remains in the throes of the Brexit process and as May plans to step down on Friday as leader of her Conservative party.

It will be capped on Wednesday with a large ceremony in the southern city of Portsmouth to mark the 75th anniversary of the D-Day landings in 1944, when some 160,000 British, US, French and other Allied troops landed in Normandy, in German-occupied western France, in World War II.

The president then plans to travel to Ireland and France.

"As we face the new challenges of the 21st Century, the anniversary of D-Day reminds us of all that our countries have achieved together," the queen said in her speech.