Gunmen kidnap 2 Americans, 2 Canadians in Nigeria, police say They were allegedly abducted by gunmen in northern Nigeria.

 -- Two Americans and two Canadians who were traveling through northern Nigeria have been kidnapped by gunmen, police said.

Police officers were escorting the four foreigners through Kaduna state on Tuesday night when they were ambushed on a roadway in Kagarko, Kaduna state police spokesman Mukhtar Aliyu told ABC News.

A gun fight ensued between the police officers and the attackers, and two policemen were killed and another was wounded. The gunmen abducted the foreigners and took off, according to Aliyu.

The foreigners had visited Kafanchan and Kaura in Kaduna state and were heading back to Nigeria's capital city, Abuja, at the time of the ambush.

Police aren't releasing the identities of the foreign nationals for security reasons.

"Our men are doing everything possible to rescue them," Aliyu told ABC News via telephone Thursday morning.

An official at the U.S. Department of State told ABC News on Wednesday that the government was aware that two citizens were reportedly kidnapped in Nigeria, but said no further information was available at this time.

A spokesperson for Global Affairs Canada told ABC News on Wednesday it was aware that two of their nationals were reportedly abducted as well. The Canadian government wouldn't release further details due to privacy concerns.

"Consular officials in Nigeria are in contact with local authorities to gather additional information," the spokesperson said.

According to the U.S. Department of State, violent crime, including kidnapping, is common throughout Nigeria.

ABC News' Sarah Kolinovsky contributed to this report.