Fireworks are suspected as the cause of Saturday's forest fire that left six dead and three injured in east China's Zhejiang Province, a local official said Sunday.

The blaze was likely started around noon Saturday when people set off fireworks at the graves of relatives in Fulin Village, Chun'an County, said Hong Shanfu, deputy head of the county publicity department, citing an initial investigation.

About 300 people, including fire-fighters and villagers, had managed to put out the fire at about 10:20 p.m..

Six villagers, including a college student who had returned home for the Lunar New Year holiday, died fighting the blaze, Hong said.

The provincial government Saturday urged lower level authorities to stay vigilant against forest fires as many people were setting off fireworks and burning paper money in tribute to their ancestors.