A previously unknown Iraqi group has taken seven hostages and says it will start to kill them unless their Kuwaiti employer pulls out of the country.
The group linked its hostages to "US cowboy occupiers"
A group, calling itself The Holders of the Black Banners, said it had seized the drivers - three Indians, three Kenyans and an Egyptian.
The Indian government
and relatives of the Kenyans have appealed to the group to release the hostages.
A statement by the group said the firm had until Wednesday evening to comply.
The group said all who dealt with "American cowboy occupiers" would face "the fires of the Mujahideen".
Rana Abu-Zaineh, from Kuwait's KGL Transport Company, told AP news agency: "The most important thing for KGL is that the seven people arrive here safely and talk to their relatives, whatever that takes."
The Egyptian embassy in Baghdad confirmed to the AFP news agency that one of its nationals, a truck driver named as Mohammed Ali, had been kidnapped by the group.
India was working to secure the release of its three citizens through its embassy in Baghdad, a foreign ministry spokesman said.
The Kenyan government was reported in the Kenyan media to have secured contact with the militant group.
Relatives of one of the Kenyan captives, Ibrahim Khamis, have appealed for his release.
"He is a good Muslim trying to support his wife and four children and the kidnappers should consider that," said his brother Faiz Khamis.
"Our brother bore no ill-will to the people of Iraq."
The group made its threat in a statement issued to news agencies and in a videotape aired by al-Arabiya television.
It came a day after another militant group in Iraq released Filipino truck driver Angelo de la Cruz because his country had pulled out its 51-strong peacekeeping force.
The group said it would behead one of its hostages every 72 hours if the company did not leave the country.
The statement set a deadline starting at 2000 local time (1600 GMT) on Wednesday.
The militants also called on India, Kenya and Egypt - none of which have troops in Iraq - to withdraw their personnel.