PESHAWAR, Pakistan, Oct 27 (Reuters) - A blast at a religious seminary in Pakistan's northern city of Peshawar on Tuesday killed at least seven people, including children, and injured dozens, officials said.

"The blast took place in a madrassa where unknown people had planted explosives in a plastic bag," a police officer said on condition of anonymity as he was not authorised to speak with media. Children were among the dead, he added.

A spokesman for the Lady Reading Hospital nearby said it had received seven dead and 70 wounded patients, many with burns suffered in the blast. (Reporting by Jibran Ahmad; Writing by Charlotte Greenfield; Editing by Clarence Fernandez)