NEW DELHI, Feb. 20 (Xinhua) -- At least four people have died and 11 hospitalized following a gas leak in the northern Indian state of Punjab Tuesday, police said.

"Ammonia gas leaked from a food processing plant at Shambhu in Rajpura. While four local residents died after inhaling the gas, those injured have been admitted to a local hospital," a police official said.

A probe has been ordered into the incident, he added.

Gas leak incidents are not uncommon in India, the notable being the Bhopal gas tragedy.

Some 4,000 people were killed when methyl isocyanate gas and other chemicals leaked from the U.S.-based Union Carbide's pesticide plant in the central Indian state of Madhya Pradesh's capital Bhopal in 1984. The incident was considered the world's worst industrial disaster.