LAGOS, Nigeria -- A Nigerian police spokesman says two Canadians and two Americans who were kidnapped in north-central Kaduna state on Tuesday have been released.

Kaduna state police spokesman Mukhtar Aliyu says they were freed Friday night and are in good condition. He says they have been taken to the capital, Abuja, where they are undergoing medical observation because of the trauma they experienced.

Aliyu says one suspect has been arrested in connection with the kidnapping. Gunmen ambushed the foreigners as they travelled from Kafanchan in Kaduna state to Abuja. Two police escorts were killed.

The spokesman earlier said the foreigners are investors setting up solar stations in villages around Kafanchan.

Kidnapping for ransom is common in Nigeria, but Aliyu says no ransom was paid in this case.