Six people have died and seven others are seriously ill in hospital after they mistakenly ate poisonous plants Sunday in northwest China's Xinjiang Uygur Autonomous Region, the local government said Monday.

The victims were all workers at an iron mine in Toli County, Tacheng Prefecture, a county government spokesman said.

He said the workers fell ill after they ate potherbs they had mistaken for celery.

Four of the victims died on the way to hospital. Two others failed to respond to emergency treatment and died Sunday night.

As of midday Monday, the seven were in critical conditions.

Local authorities have launched an investigation.

(Xinhua News Agency May 31, 2010)