US President Joe Biden on Saturday headed to London to attend the funeral of Queen Elizabeth II.

The state funeral, the first in Britain since the death of Winston Churchill in 1965, will take place Monday at Westminster Abbey in London at 11:00 am (1000 GMT).

Biden will be among several hundred leaders from around the world attending the somber and historic event, along with some 2,000 other guests.

While the leaders of the European Union, France, Japan and many other countries will attend, those of Russia, Afghanistan, Myanmar, Syria and North Korea were not invited.

On Sunday, Biden will attend a reception organized by King Charles III, the White House announced. The two men spoke by phone on Wednesday, with Biden vowing to preserve the "special relationship" between their countries.

A meeting Biden was to have held Monday with new Prime Minister Liz Truss at her Downing Street residence has been canceled, US and British officials announced, but the two instead will meet Wednesday in New York when both arrive to attend the annual United Nations General Assembly.

World leaders were beginning to gather in London on Saturday to prepare for Monday's funeral.

Their presence -- along with that of hundreds of thousands of mourners from across Britain and around the world -- poses an extraordinary challenge to British police.

It will be London's largest ever policing event, the city's Metropolitan Police force said Friday.

More than 2,000 officers have been drafted from across the country to help Scotland Yard.

After the funeral, the queen's coffin will be transferred by royal hearse to Windsor Castle, west of London, for a committal service.

That will be followed by a family-only burial in which the queen will be laid to rest alongside her late husband Philip, both her parents and her younger sister.