Oleg Sheikin, the spokesman for Tekhnopromexport, said all construction work had been stopped at the site after the incident.
Armed men in Iraqi Interior Ministry uniforms burst into the office of Al-Said, an Iraqi company, at 8 a.m. local time Monday, Sheikin quoted the company's head as saying. Abdel Salyam Muhammad Said said the men demanded IDs and computer information, and then took the 18 Iraqi citizens with them.
Al-Said is the main contractor of Tekhnopromexport, which is building a power plant 40km south of Baghdad. According to the current contract, the plant will have three units each with a capacity of 210 MW.
"All technical documents related to this contract were inside the company building," Sheikin said.
Six of the 18 abducted employees, all Shiites, were later released, while the rest - Sunnis - are still being held the country's Interior Ministry, Said said.
The six Shiites were kidnapped again Wednesday morning, this time from their homes in Baghdad. Said said they might be dead.
"The abduction of company employees and the termination of work on the site is a blow not only to Iraqi but to Russian economic interests," Said said.
Al-Said's office is situated on a street guarded by government forces, near the Russian embassy in Iraq.
