Niger has signed a memorandum of understanding with Chinese state-owned oil giant China National Petroleum Corp (CNPC) worth $400 million linked to the sale of crude oil from its Agadem oilfield, Niger state television RTN reported late on Friday.

RTN did not provide details on the agreement. Niger's military authorities and CNPC could not be reached for comment.

"China is a great friend to Niger; we can never say it enough," Prime Minister and Minister of Economy and Finance Ali Mahaman Lamine Zeine said at the signing ceremony, which was broadcast by RTN.

"This signature demonstrates the friendship ... and fruitful cooperation between the two states," Chinese ambassador Jiang Feng said.

An export pipeline project backed by CNPC subsidiary PetroChina (601857.SS), opens new tab was officially launched last November, linking the Agadem oilfield to the port of Cotonou in neighbouring Benin.

Previously, the West African country had a small oil refinery with capacity of around 20,000 bpd that mostly supplies Niger's domestic fuel market.