"We can confirm that US forces in Niger commenced ISR flights to monitor for threats for purposes of force protection," the US Africa Command spokeswoman said, referring to intelligence, surveillance and reconnaissance.

"We have secured approvals from appropriate authorities," she said, noting that "the US always reserves the right to conduct operations to protect our forces and personnel, if required."

While the flights have resumed, other activities with Nigerien forces such as security assistance training and counterterrorism cooperation -- key parts of US efforts to help the Sahel region fight jihadist groups -- have not, the spokeswoman added.

Washington has some 1,100 military personnel in the country, but the Defense Department says they have largely remained on bases since the military takeover.

Niger's President Mohamed Bazoum was toppled on July 26 by members of his guard and was detained along with his family.

The West African bloc ECOWAS has taken a hard line on Niger following a cascade of coups in the region, threatening to use force to restore civilian rule.

The Pentagon said last week that it was repositioning forces from a base in the capital Niamey to one in the Agadez area, describing the move as a precautionary measure.