Russia is close to finishing the construction of Iran's first nuclear power plant and is currently making final adjustments, Foreign Ministry spokesman Andrei Nesterenko said on Tuesday.

Russian Energy Minister Sergei Shmatko said on Monday that the launch of the Bushehr nuclear plant in southern Iran may not take place before the end of this year, as earlier planned.

"We are fully committed to completing this project. Russia has already supplied fuel for the reactor that has been built, and currently start-up and adjustment work is underway. Close attention is being paid to ensuring the safety of the reactor's work," Nesterenko said.

"Upon completion of all necessary operations and tests, the reactor will be launched within the timeframe agreed with the Iranian side," he said.

Nesterenko said that Russian and Iranian specialists have yet to resolve certain technical problems.

He stressed that Russia's work on the project is not affected by the international controversy over Iran's nuclear program.

Russia has frequently delayed the launch of the plant in the Islamic Republic, citing financial or technical problems. Iran is at the center of an international dispute over its nuclear ambitions, amid Western suspicions that the program has military goals, and is subject to UN sanctions.

The $1 billion plant in southern Iran was expected to be launched in 2009.

Nesterenko also said that Moscow is complying with its international commitments in its military and technical cooperation with Iran.

"Russia has for many years been carrying out military and technical cooperation with Iran with the strict observance of its international commitments," Nesterenko said in response to a question about the supply of S-300 surface-to-air missiles.

The spokesman said Russia is supplying only defensive armaments that have no potential to destabilize the situation in the region.

A top Iranian military official last Friday urged Russia to honor its bilateral military contract and deliver the promised S-300 surface-to-air missiles, according to the Mehr news agency.

Gen. Hassan Firouzabadi said Russia was six months behind schedule with deliveries of advanced air-defense systems.

Russia signed a contract with Iran on the supply of S-300 air defense systems to the Islamic Republic in December 2005. However, there have been no official reports on the start of the contract's implementation since then.

The possible deliveries of S-300 missiles to Iran have aroused serious concern in the West and in Israel.

The latest version of the S-300 series is the S-300PMU2 Favorit, which has a range of up to 195 kilometers (about 120 miles) and can intercept aircraft and ballistic missiles at altitudes from 10 meters to 27 kilometers.

It is considered one of the world's most effective all-altitude regional air defense systems, comparable in performance to the U.S. MIM-104 Patriot system.