A Ugandan activist campaigning to stop the development of a $5 billion crude oil pipeline in East Africa by France's TotalEnergies and others has been detained by Uganda's military according to the group he works.

Stephen Kwikiriza from the Ugandan environmental pressure group Environment Governance Institute (EGI) has been campaigning to halt the East African Crude Oil Pipeline (Eacop).

The 1,445-km pipeline is to carry crude from oilfields in Uganda's west through Tanzania to a port on Tanzania's coast.

The pipeline's opponents, including Human Rights Watch, say the project will displace hundreds of thousands of people, destroy fragile ecosystems and undermine efforts to limit carbon emissions.

In a statement, EGI said the Ugandan military had detained Kwikiriza on Tuesday in the capital Kampala, according to a text message he sent to a colleague. His whereabouts are unknown, said EGI, which works with other groups to oppose the pipeline.

Pressure groups accuse Ugandan authorities of harassing activists who have been campaigning against Eacop. Ugandan authorities deny the accusation.

Last month seven activists were briefly detained outside the Chinese embassy in Kampala as they prepared to hand over a petition to the Chinese ambassador asking China to not fund the pipeline.