The government of Chad and Chinese engineering firm CAMC on Thursday signed a $1 billion (700 million euro) deal to build a new international airport north of the capital N'Djamena.

The airport with an ultra-modern terminal "will cost a billion dollars and will be financed by the state of Chad through a loan from a Chinese bank," Infrastructure Minister Adoum Younoussmi said at the signing ceremony.

Negotiations over the loan would start April 28 with the Chinese government, he said.

The project also includes building a motorway between the airport at Djermaya and the capital, 40 kilometres (25 miles) to the south.

One million passengers a year were expected to use the airport, which should be completed in four years.

N'Djamena's current airport, Hassan Djamous, is situated near the centre of the capital, which is growing rapidly and where property values have soared.