An attacker has stabbed two people to death and wounded another at an Ikea store in the central Swedish city of Vasteras.

Police in the city, some 60 miles west of the capital Stockholm, said they had detained a man on suspicion of murder.

A man and a woman had been killed in the attack and a third person was seriously injured, police added.

Martina Smedberg, spokeswoman for Ikea Group, said the attack occurred with no warning and they had no idea of a possible motive.

"There have been no known threats against Ikea," she said. "The building was evacuated and closed immediately after the attack."