Update as of 3:49 a.m. EDT: At least 13 people, including children, have been killed by a bomb that exploded at a viewing station where many locals had gathered to watch a World Cup game Tuesday, Reuters reported, adding that while no one had yet claimed responsibility for the incident, Yobe state where the town of Damaturu is located, is a hotbed of activity for Islamist insurgent group Boko Haram.

A Reuters correspondent reportedly counted the number of dead at a local hospital as 13, and the number of injured to be at least 20. It is unclear, the report said, if the bombing was carried out by a suicide bomber, as some local sources at the scene claimed, or if a device was planted at the venue by someone.

UPDATE, 8:30 p.m.: Several pickup trucks carrying bodies arrived at the nearby General Sani Abacha Specialist Hospital, a hospital source said, adding: "There are also many casualties in the emergency room."

(Reuters) - An explosion rocked a venue in the town of Damaturu in northeast Nigeria where fans had gathered to watch a World Cup soccer match on Tuesday, a security source said.

There was no immediate word on casualties but a Reuters witness near the scene heard a loud boom. Some residents said they also heard a second explosion.

Damaturu is the capital of Yobe state, an area that has been devastated by attacks from militant Islamist group Boko Haram which in April abducted more than 200 girls from a school in neighbouring Borno state.

The Nigerian government has advised residents to avoid gathering in public to watch the World Cup, concerned about possible attacks.

Boko Haram has killed thousands since 2009 in its push to carve out an Islamic state in Nigeria's restive north.