US military trainers deployed to Nigeria are using high-powered drones for surveillance and intelligence gathering, the Nigerian military said on Saturday.

The drones are being deployed from an air base in Bauchi state. Although capable of strikes, they are only being used to detect, track and disrupt terrorist activity, according to a military official.

About 100 US troops arrived in Nigeria last month to help train soldiers in their fight against Islamic militants and other armed groups. The Americans are not serving in combat roles, both countries have confirmed.

Nigeria is facing a long-running battle with dozens of militant groups, including Boko Haram and affiliates of the so-called Islamic State. Other armed groups specialise in kidnapping for ransom and illegal mining.

Last year, America launched strikes on jihadist groups in Nigeria’s northwest. US President Donald Trump has criticised Abuja for failing to stop violence in the country. He’s claimed that Christians are being persecuted but analysts say the attacks target people from all faiths.

Washington previously operated a major drone base in neighbouring Niger, which has since shuttered after the junta ordered US forces to depart the country.