Prince Harry and Meghan Markle’s children have reportedly changed schools in the U.K. just days after starting classes, with security concerns said to be behind the sudden move.

Prince Harry and Meghan returned to the U.K. with their children, Archie, 7, and Lilibet, 5, after spending six years living in the United States. The family had been settling into life in England, but their children’s school arrangements have now reportedly changed.

According to reports, Archie and Lilibet attended their first U.K. school for only two days before being moved to another school.

The change is reportedly linked to concerns about the children’s security. Harry has been involved in a long-running dispute over his security arrangements in the U.K. since stepping down as a working royal, and the issue has remained a major concern for the Duke and Duchess of Sussex.

The reported school change comes as the family adjusts to their new life back in Britain.

Harry makes first public appearance after returning to the U.K.

Harry made his first public appearance since returning to Britain on September 17, attending the inaugural Invictus Spirit Awards at the Old Royal Naval College in London.

The Duke of Sussex appeared in a black suit, white shirt and black bow tie, wearing several military and royal medals, including the Afghanistan Operational Service Medal and his KCVO insignia.

Despite the changes happening in his family’s private life, Harry appeared in good spirits as he reunited with members of the Invictus community.

“It’s good to be back on British soil,” Harry told PEOPLE at the event.

Harry founded the Invictus Games in 2014 after being inspired by the Warrior Games in the United States. The international event gives wounded, injured and sick military service members and veterans an opportunity to compete in adaptive sports.

During the awards ceremony, Harry also delivered an emotional speech about what he called the “Invictus Spirit.”

“Sometimes victory is getting out of bed or asking for help,” he said, highlighting the everyday achievements of veterans and their families.

The Duke added that victories can also mean finding work, reconnecting with family or discovering a new sense of purpose after military service.

As Harry and Meghan continue adjusting to life in the U.K., their children’s reported school move shows that security remains an important part of the family’s return to Britain.