TEHRAN, Iran - Iranian state TV says the country's first nuclear power plant has stepped up operations after years of delays.

Senior Iranian and Russian officials attended celebrations Monday for the official launch of the 1000-megawatt Bushehr plant in southern Iran.

It began to generate between 350 to 400 megawatts of electricity, equal to 35 to 40 per cent of the reactor's full capacity.

The Russian-built plant was connected to the national power grid for a test run Sept. 4, generating 60 megawatts.

The launch of the plant has been delayed for years. The U.S. and its allies accuse Iran of using its civilian nuclear program as a cover to develop nuclear weapons. Iran denies the claim.