LONDON -- A woman and a man died, and three others were injured after an explosion at a residential address in Bristol, southern England, following what police described as a "domestic-related incident," local police said on Sunday.

Avon and Somerset Police said officers were called at 6:17 am to reports of a domestic incident at an address on Sterncourt Road. An explosion occurred shortly afterwards, at around 6:30 a.m., before officers arrived at the scene.

Superintendent Matt Ebbs told media in Bristol that the two people who died were a woman and a man. Three other people, including a man, a woman and a child, were taken to hospital with "minor injuries," he said.

Police cordoned off the area, evacuated nearby residents and declared a major incident. Ebbs said officers were not seeking anyone else in connection with the explosion and that the incident was not being treated as terrorism-related.

Police are also carrying out inquiries at a separate property in Speedwell, suburban Bristol, which was linked to the man who died.

Ebbs said the cordon was put in place to protect the public and allow inquiries and specialist searches by the British Army's explosive ordnance disposal unit as a precaution.

The clarification came amid heightened security concerns in Britain. In a separate incident, four people were injured in a shooting in Brixton, south London in the early hours of Saturday.

Britain last week raised its terrorism threat level to "severe," the second-highest level, after police declared a stabbing attack in London's Golders Green area "a terrorist incident."