Russia has offered to airlift more than 800 of its nationals and former Soviet citizens out of Iraq as the abduction of foreign citizens continues.
Security is tight as 40 foreigners have been abducted since last week
Three Russian and five Ukrainian energy workers were kidnapped in Baghdad this week and briefly held before being released by their captors.
Other governments have advised their citizens to also leave the country.
Japan is investigating reports that two more of its citizens have been abducted in addition to three already held.
The foreign ministry in Tokyo was reacting to media reports that two citizens had been abducted outside Baghdad on Wednesday.
A French journalist kidnapped on Sunday has now been released. Alexandre Jordanov was in good health after his ordeal, French officials said.
The US-led coalition said this week that about 40 foreigners were being held hostage by militants after two weeks of unrest in both Sunni and Shia parts of Iraq.
France and Germany have formally asked their citizens to leave Iraq while the UK has advised against travelling there unless absolutely essential.
Firms to choose
Russian energy firm Tekhnopromexport accepted the evacuation offer while another top contractor, Interenergoservis, said most of its employees might stay.
Russian Foreign Minister Sergey Lavrov said it was up to the companies to decide whether to join the evacuation.
Seven Russian flights will take off from Baghdad and Kuwait on Thursday and Friday.
Several of the Russian and Ukrainian hostages released on Tuesday said the gunmen freed them after discovering they worked for a company from Russia, which opposed Iraq's occupation.
Russian firms are involved in reconstruction projects in power, transport, oil and gas sectors.
Many of them hire cheaper workers from other former Soviet states such as Ukraine.