The second fuel cargo is expected to be shipped to the port later this week.
Lukoil, which stopped its activities in Iran under US pressures in April, resumed selling gasoline to Iran in participation with its trading and supply arm, Litasko, and China's state-run firm, Zhuhai Zhenrong.
Following the June 9 UN Security Council sanctions against Iran, the US and European Union took unilateral measures against the country over its nuclear program.
Moscow has repeatedly voiced opposition to unilateral sanctions against Iran. Russian Energy Minister Sergei Shmatko recently said that the United Nations sanctions against Iran would not prevent Russian firms from providing Tehran with oil products.
Bushehr plant to go active
Russia announced Friday it will begin the startup next week of Iran's only atomic power plant, giving Tehran a boost as it struggles with international sanctions and highlighting differences between Moscow and Washington over pressuring the Islamic Republic to give up activities that could be used to make nuclear arms.
Uranium fuel shipped by Russia will be loaded into the Bushehr reactor on Aug. 21, beginning a process that will last about a month and end with the reactor sending electricity to Iranian cities, Russian and Iranian officials said.
"From that moment, the Bushehr plant will be officially considered a nuclear energy installation," said Sergei Novikov, a spokesman for the Russian nuclear agency.
The US, which possesses and has used nuclear weapons in the past, accuses Iran of pursuing a military nuclear program. Tehran rejects the allegations, arguing that as a signatory to the Nuclear Non-Proliferation Treaty and a member of the International Atomic Energy Agency it has the right to use nuclear technology.