A fire in a bus that killed 47 people and injured 37 others in China's Fujian Province, on Friday, is being investigated as a "serious criminal case" as the evidence in the initial investigation pointed to criminal act, local media reports said on Saturday.

In a breakthrough development, Chinese police said they have identified a suspect who might have caused the fire and added that further investigation is underway.

Fire that broke out during the Friday evening rush hours gutted the bus belonging to the new express system known as Bus Rapid Transit, while it was travelling on an enclosed and elevated highway in the Xiamen city.

Citing investigators Xinhua said the fire did not appear like an accident, as the tires and oil tank of the bus remained intact.

"It's a serious criminal case," the Ministry of Public Security, the national police agency, said in a statement on website.

An Associated Press report quoting Xiamen's official news site witnesses heard sound of explosions ten minutes after the bus caught fire.

Chinese President Xi Jinping, who is in California for a summit with President Barack Obama asked his government to take measures to prevent such incidents, Xinhua reported.

"Life is precious, and lives cannot be sacrificed in the pursuit of development," Xi said. "Lessons must be learned from this spilling of blood and bitter experience."

The incident occurred just days after fire at a poultry farm killed 120 people in northeast China.

Buses and public transport has been targeted in China in recent years. On June 5, 2009, 28 people were killed and 70 others were injured when an unemployed youth set ablaze a commuter bus in southwest Sichuan province.  

In 2005, 31 people were injured when a 42-year-old farmer with terminal lung cancer blasted a home-made bomb aboard a bus in southeast China.