Police are hunting a man who they say forced his way into a hotel room and took his two young children from their mother.
Two-and-a-half year old Na'llah Khan and her brother, 10-month-old Sulailman Khan, were taken from a hotel at about 5pm, yesterday, according to Nottinghamshire Police.
The pair were in their mother's care at a hotel in Stoke-on-Trent in Staffordshire at the time.
Police say they were taken by their father Saleem Tahir, 40, who is from Nottingham, and are also believed to be with their 67-year-old grandmother Denise Smith-Sellers.
They were both last seen in Birmingham three hours after the incident, at about 8pm, yesterday.
Staffordshire Police is urging the pair and anyone else with information to call them urgently on 101.
The force said officers were concerned for the children's welfare and were now seeking the safe return of the youngsters to their mother's care.