A series of blasts that rocked London on Thursday killed at least 12 people and wounded scores, police and hospital officials and witnesses said.

However, the death toll can be at least 40 and more than 300 were injured, Xinhua reported.

CNN television said at least 10 people were killed in an explosion at King's Cross station. It said one of its producers at the scene had been told of "double-digit fatalities."

Police said two people were killed in an explosion at the Aldgate East underground station. A doctor at the station said at least 90 people were wounded in the blast.

The Royal London Hospital in the east of the capital said 95 people were being treated, seven of them in a critical condition and 10 serious. It was not clear how many of them had been brought in from Aldgate.

St. Mary's Hospital in west London said 80 wounded had been brought in, four of them critical and nine serious. Officials said the casualties were believed to have come from a blast at Edgware Road underground station in East London.

Other hospitals said they had received wounded but declined to give numbers.

A spokesman for the ambulance service said there had been at least seven attacks.

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Sources: China Daily/Agencies