The Russians, who work for the Aluminum Smelter Company of Nigeria (ALSCON), controlled by Russian aluminum giant RUSAL, were abducted by gunmen who broke into their residential premises in the southeastern town of Ikot Abasi Sunday, killing their Nigerian driver.
"Last night we were able to talk to the abducted Russians and learn they were alive and feeling well. That is all I can say at the moment," a diplomat said.
None of the militant groups active in the country has so far claimed responsibility for the abduction or put forward demands, Russia's Foreign Ministry said earlier. But the employees are widely believed to have been abducted for ransom.
RUSAL said it had stepped up security at the residential complex for its employees. Press spokeswoman Olga Sanarova said the company was continuing talks with Nigerian authorities on measures to have the Russians released. Their names have not been disclosed for security reasons.
Nigeria's ambassador to Russia was summoned Monday to the Foreign Ministry over the abduction.
Sergei Lavrov, currently on a visit to South Korea, told journalists: "The Nigerian ambassador in Moscow is to arrive at the Russian Foreign Ministry today for talks on the subject."
Militants fighting against the Nigerian government for greater autonomy in the oil-rich Niger Delta have intensified their attacks lately on industry facilities that are largely run by Western companies.
About 40 people, largely employees of oil companies, have been abducted and released in the country since January 2006. They were mainly nationals of the United States, the United Kingdom, Germany, Turkey and the Philippines.
A Belarusian woman who worked as a senior manager with a local branch of the British services company Compass Group, was kidnapped May 5 and released 12 days later.