LONDON — British police on Saturday said that an armed intruder was arrested on Christmas morning on the grounds of Windsor Castle, the main residence of Queen Elizabeth II, where the British monarch was celebrating Christmas.

“The man has been arrested on suspicion of breach or trespass of a protected site and possession of an offensive weapon. He remains in custody at this time,” Thames Valley Police Superintendent Rebecca Mears said in a statement.

The 19-year-old man was arrested after he was found entering the grounds of the castle at around 8:30 a.m., police said. He did not enter any buildings.

“Members of the royal family have been informed about the incident,” Mears said. “We do not believe there is a wider danger to the public.”

A spokeswoman for Buckingham Palace declined to comment on the incident.

The queen had been planning to host Christmas this year at her Sandringham estate in Norfolk, England. But those plans were scrapped, for the second year in a row, following a spike in coronavirus infections — confirmed daily cases hit a record high on Saturday.

Instead, the queen spent Christmas Day at Windsor Castle, her main residence since the start of the pandemic in 2020. She was joined by a small group of family members, including her eldest son, Prince Charles, and his wife, Camilla.

This was the queen’s first Christmas since the death of her husband, Prince Philip, in April at age 99. The queen paid tribute to him in her annual Christmas Day speech, which was broadcast Saturday was but recorded last week.

Referring to Philip, the queen said that there was “one familiar laugh missing this year.”