Tanzania's environmental watchdog said on Thursday it has fined nine oil companies a total of 5.1 billion Tanzanian shillings (about 2.2 million U.S. dollars) over violation of environmental rules.

Samuel Gwamaka, the Director General of state-run National Environment Management Council (NEMC), said the nine companies have been fined after it was established that they constructed filling stations across the country without undergoing an environmental impact assessment (EIA).

"The nine oil companies should pay the fines within 14 days beginning Sept. 10," Gwamaka told a news conference in the commercial capital Dar es Salaam.

Gwamaka said an ongoing crackdown on oil companies that are operating filling stations without undergoing the EIA across the country has established that there are about 393 companies flouting the environmental rule.

He said NEMC has established that most of the oil companies have constructed filling stations without EIA, adding that the crackdown was continuous.