British police said on Saturday they had briefly evacuated London's Trafalgar Square, near which Queen Elizabeth's Platinum Jubilee celebrations would later take place, but said shortly after that the alarm had been lifted, Reuters reported.

"The incident has already been resolved and the square will be reopened in due course," the police said.

A police spokesman said there had previously been numerous checks in the area, which is a short distance from the concert venue at Buckingham Palace later that day.

According to him, the incident is believed to be related to a suspicious package.