Three Chinese military ships are in Nigeria on a rare visit which officials say is aimed at improving maritime security.

The arrival of the fleet - which is led by a destroyer - comes six months after a new billion-dollar deep sea port was opened in Lagos.

It was Chinese-built and China has retained a majority shareholding in the company that runs the facility.

Correspondents say the port and naval visit are further signs of China's growing presence in Africa.

Nigeria is a major oil supplier to China.

In a statement, China's ambassador in Nigeria Cui Jianchun described the event as a major move in China-Nigeria relations saying it "demonstrates the high degree of political mutual trust between the two countries which will have a profound impact on development".

The Nigerian navy led by Rear Admiral JD Akpan expressed "willingness to work with China to tackle maritime security threats and maintain stability in the Gulf of Guinea".

Last year US defence officials expressed concern that America's national security could be under threat if China sets up a military base on the West African coastline.

In 2017, China opened its first overseas naval base in Djibouti on the East African coast.