Four people were killed and 22 others injured after an explosion hit an oil company in Egypt's Suez city, local hospital sources told Xinhua on Saturday.

The blast, which occurred at around 6 p.m. local time (GMT 1600) , hit one of the tanks of Nasr Petroleum Company and caused a big blaze. Troops were mobilized to evacuate the company and help quench the fire which has spread to other oil tanks.

Dozens of fire-fighting trucks and four helicopters were still struggling to put out the fire near midnight.

Meanwhile, the official MENA news agency quoted the Health Ministry as saying that at least one died and 12 were injured.

The exact cause of the explosion remains unclear till the moment.