The Russian embassy in Libya's capital, Tripoli, was attacked by unknown gunmen, according to the Russian foreign ministry.
"In Tripoli ... a shooting occurred and there was an attempt to enter the territory of the Russian embassy in Libya," said Foreign Ministry spokesman Alexander Lukashevich, speaking on Russian state television.
"According to the most preliminary information there were no injuries among members of the Russian diplomatic mission," he added.
Diplomatic sources in Libya are reporting that security guards fired shots to disperse about 60 people that had approached the embassy, and quickly secured the compound, according to Reuters news agency.
They say the attack does not appear to be linked to any militant group. A crowd had come to protest and look for a Ukranian woman who allegedly killed a Libyan on Tuesday and then sought refuge in the Russian embassy.
In a separate attack in the eastern city of Benghazi, armed men shot dead a Libyan marine colonel and his son.
The shooting of Col Salih al-Hidary followed assaults that killed two other officers in Benghazi a few days eariler.
Since the overthrow of Muammar Gaddafi two years ago, clan and tribal rivalries have flourished and security services, themselves factionalised, have struggled to maintain order.
There have been a number of attacks on Western diplomatic missions, the worst being directed against the US consulate in Benghazi.
Fighters allegedly linked to al-Qaeda affiliates attacked the US consulate and killed Ambassador Christopher Stevens and 3 other Americans on September 11 last year.
Western powers, using air power, led the military campaign that ultimately toppled Gaddafi. Russia, however, did not take part in the action and condemned what it called the West's abuse of a United Nations Security Council to intervene.