The Greater Tortue Ahmeyim (GTA) field shared by the two west African countries began operating on December 31.

It was jointly developed by BP, American company Kosmos Energy, Mauritanian hydrocarbons company SMH and Senegal's state-owned Petrosen.

A gas leak at one of the GTA wells was discovered on February 19, the Mauritanian environment ministry said on Facebook last week.

"A thorough investigation to control the situation and minimise any potential environmental impact" is being carried out, the ministry said.

In a statement sent to AFP on Wednesday, BP said "low-rate subsea gas bubbles" were discovered at a GTA well.

" We have a plan to stop the bubbles, as part of that plan we have mobilised specialised equipment and personnel," it added.

"Considering the low rate of release and the gas and condensate properties, the environmental impact is currently expected to be negligible," BP said, adding there was "no risk to employees".

The site's three other wells continue their production activities while the repairs are carried out, it said.

Contacted by AFP, Senegalese authorities did not respond.

A Dakar-based think tank, LEGS-Africa, called for people in Senegal to be informed of the cause, extent and impacts of the leak.

The site aims to produce around 2.5 million tonnes of liquefied natural gas per year.

Delayed several times, the start of production was highly anticipated in both countries, with hopes high it will help transform their economies.