Firefithers search for survivors among the debris after an explosion-triggered building collapse in Suzhou city, East China's Jiangsu province on June 11, 2013. [Photo/Xinhua]

The death toll of a building collapse in East China's Jiangsu province on Tuesday morning rose to 11, according to a press briefing on Tuesday night.

Twenty people were buried after a three-storey office building collapsed in Suzhou city at 7:26 am following an explosion of the staff canteen on the first floor. Eleven of them died in hospital, according to the press briefing organized by the Suzhou municipal government.

The remaining nine are still receiving treatment in two local hospitals, according to the press briefing.

The office building belonged to a liquefied gas sales branch of the Suzhou Gas Group Co Ltd.

A preliminary investigation showed that the blast was caused by a gas leak.