British police say a 33-year-old woman and her four children aged 4 to 12 may be trying to reach an Islamic State group-controlled area of Syria.

The Metropolitan Police says Zahera Tariq and her children left their London home on Tuesday and flew to Amsterdam. A relative reported the family missing the next day.

Commander Richard Walton of Scotland Yard's Counterterrorism Command said Saturday that police "have some concerns that Zahera may be thinking of travelling to Syria, (though) there is no current information to suggest that she's already travelled there."

Several families with young children are among more than 700 Britons who have traveled to areas controlled by the militant group.

Police say more than 40 women and girls have gone to Syria from Britain in the last year.