London fire officials say a suspected gas leak touched off an explosion in the basement of a London hotel, injuring 11 people and forcing the evacuation of hundreds of guests.

The London Fire Brigade said Saturday that five of the 11 were seriously injured and some 400 guests were evacuated to a nearby hotel after the blast caused extensive damage to the basement and ground floor. Five cars on a neighboring street were also damaged.

The explosion at the five-star Churchill Hyatt Regency Hotel took place just before midnight Friday.

Six fire engines and 35 firefighters responded, together with rescue and hazardous materials teams. Officials say the cause of the blast is being investigated, but a gas leak is suspected.

The luxury West End hotel has 434 rooms and suites.