HEMEL HEMPSTEAD, England, Dec 11 (Xinhuanet) -- Massive explosions rocked a fuel depot north of London early Sunday morning, emitting smoke hundreds of meters into the sky and injuring 36 people, two of them seriously.

    "All indications at this stage are that this was an accident. However clearly we will keep an open mind," Hertfordshire Chief Constable Frank Whiteley told a press conference, stressing that earlier rumors a plane was involved in the incident were unfounded.

    The first blast happened at 0603 GMT, followed by two explosions some 20 minutes later, at the Buncefield fuel depot near Hemel Hempstead 50 km north of London, the country's fifth largest fuel distribution center which supplies airports across the region, including Heathrow and Luton.

    At Heathrow airport some flights were reportedly forced to delay their landing due to the smoke, but Luton airport was said to be operating as usual.

    The skies over Buncefield were still blackened with a wall of smoke, with thick clouds of smoke spreading toward the south-east and south-west.

    The area around the site has been evacuated and arterial roads nearby closed, while police have advised residents living nearby to keep their windows and doors closed because of fumes.

    Experts said that under such circumstances, fire crews could only cut off the fuel supply and wait for the fire to burn out. They said the fire could last days with more explosions expected.

    Oil is brought to the Buncefield depot in an underground pipeline from tankers unloading on Britain's east coast.

    Police said there was no indication the explosion would cause fuel shortages and warned against panic-buying.

    "We are doing everything we can to support the emergency services and to bring the situation under control," said a spokesman for Total, one of the operators of the fuel depot. Enditem