United Kingdom authorities have uncovered a plot by radical British Islamists to blow up Queen Elizabeth II at a celebration next weekend marking the 70th anniversary of the end of the World War II, according to the Mail on Sunday newspaper.

London police and security services are in "a frantic race against time to thwart the assassination plot," the newspaper said.

The Queen and members of the royal family are scheduled to attend a church service and military parade in central London next Saturday to mark the 70th anniversary of Victory in Japan Day.

The Japanese surrender on August 15, 1945 – less than a week after the United States dropped atom bombs on Hiroshima and Nagasaki – brought the World War II to its conclusion.

A Metropolitan Police spokesman encouraged the public "to continue with their plans to attend or take part in events as normal.'' He said that the force's priority is "the safety and security for all those attending or involved."

The newspaper said the potential attackers were British Islamists acting on the orders of Islamic State (ISIS) commanders in Syria. Their plan was to explode a pressure cooker bomb similar to those used in the Boston Marathon bombing in 2013, which killed three people and injured more than 260.

While hundreds of ISIS converts have left the U.K. for Syria and Iraq over the past two years, others have been urged to remain at home and launch local attacks.

A Buckingham Palace spokesman refused to comment on the bomb plot, saying "It is not something we would comment on." A Scotland Yard spokesman also declined to comment.