Ports and airports have been put on alert for a couple who have gone missing with two young children.
West Yorkshire Police said Sri Lankan nationals Mohammed Fayzed and Shikiri Wahab, who may also go by the name Fatima Shikiri Wahab Aftab, are both 30 years old.
Police said the couple had broken a court order by taking the youngsters from a supervised visit.
A girl and boy, aged nine and two, were taken from an address on Roundhay Road, Leeds, on Thursday afternoon. The two made off in the direction of Spencer Place.
Anyone with information is asked to contact West Yorkshire Police.
"Officers need to speak to the two adults as a matter of urgency. An all ports warning has been issued and extensive inquiries are currently taking place in the Leeds area," said a spokesman.
Anyone who may have any information as to their whereabouts is asked to contact police immediately on 0113 2855445.