"I can not confirm if there have been negotiations or a ransom paid", Aliyu added.
It said that two of the kidnappers were also arrested in the operation while efforts are in progress to apprehend other gang members.
The Police Commissioner for Kaduna Command who addressed a news conference, said the victims were rescued around 7.30am on Saturday, January 20, in fairly good conditions and had been handed over to American Embassy in Abuja for medical attention. A gun fight ensued between the police officers and the attackers.
The gunmen killed two policemen and whisked away the expatriates.
The gunmen abducted the foreigners and took off, according to Aliyu.
The four North Americans - whose identities have not been disclosed - were on private business in Kaduna when they were snatched on the road from the town of Kafanchan to the capital Abuja.
He explained that the kidnapped foreigners were released inside a bush at about 6 a.m on Saturday morning. The safety and security of USA citizens overseas are among our top priorities.
At the time, Global Affairs Canada said it could not release further information about the Canadians due to privacy concerns. "To protect the privacy of the individuals concerned, further details on this case can not be released", Babcock said. "Canadian officials worked closely with Nigerian government officials on the ground to ensure the best possible outcome".