Police say security forces have rescued three foreigners and a Nigerian who were among seven construction workers kidnapped in an ambush on a police convoy in southeastern Nigeria that killed a driver.

Assistant Superintendent Irene Ugho, spokeswoman for southeastern Cross River state police, said no ransom was paid.

She said an Australian, a New Zealander and a South African were freed early Sunday but did not identify them by name.

Police had identified those kidnapped as Australians Jack Countentz, Mark Gabberdy and Peter Zoutenbier; New Zealander Jamal Khan, and South African Wayne Smith. They were snatched at gunpoint along with two Nigerians on Wednesday and forced from their vehicles, which were in a convoy escorted by police near Calabar, the state capital. All of those kidnapped and the driver killed worked for Australian contractor MacMahon Holdings.