The building's front was "entirely black," and all the apartment's windows and doors were "blown out," according to Nilsson. "We found a hubcap belonging to the vehicle inside the consulate," he said.
Eight people live in the consulate, which closed because of the explosion. The eight will remain elsewhere in Benghazi, Nilsson said.
In early October, gunmen attacked the Russian embassy in Tripoli, Russian state media reported. They fled after security guards killed some of the gunmen.
Russia evacuated its embassy staff and their families to Tunisia, ITAR-TASS reported.
Armed militias have roamed the country largely unchecked since the 2011 ouster of Gadhafi.
Gangs of armed men have surrounded key ministries, including the Justice Ministry, trying to force out members of the democratically elected government.
Justice Minister Salah Marghani was forced to evacuate after armed militias surrounded his ministry in April.
Libyan intelligence services have warned that the country is becoming a haven for al Qaeda to regroup and regenerate itself.
Numerous weapons left over after Gadhafi's downfall are providing groups with different motivations to form their own militias, government officials said.