Nigerian kidnappers who captured three Australians and a New Zealander after a deadly attack on mine workers have made no demands.
The men taken captive were in a group driving on the outskirts of the city of Calabar when the gunmen attacked on Wednesday.
They work for Perth-based mining company Macmahon Holdings, which mines material for processing at Lafarge Africa's UniCems cement plant at Mfamosing, in Nigeria's southeast.
A Nigerian driver was shot dead in the attack, while seven in total were kidnapped, including a South African and two Nigerians.
Another Australian managed to get away.
Foreign Minister Julie Bishop says Australian officials, including Australia's ambassador, are working with local police and the Nigerian government to determine what happened and who's behind the attack.
She told ABC radio on Friday no demands had been made.
