(CNN) The government of Niger granted the US military the authority to arm its drones in Niger earlier this week, a US official told CNN Thursday.

US defense officials had previously told CNN that the US military had been seeking the authority to arm its drones in Niger for months prior to the October ambush of US forces there that left four soldiers dead.

One official said the effort to arm US drones in Niger had gained a greater sense urgency following the deadly attack.

The chairman of the Joint Chiefs of Staff, Gen. Joseph Dunford, told reporters that a remotely piloted drone aircraft arrived overhead within minutes of the soldiers' request for support but defense officials told CNN that it was unarmed due to the previous prohibition on armed drones.

It is unclear what if any authority military commanders have to conduct drone strikes in Niger.

A spokeswoman for the Pentagon declined Thursday to speak about specific authorities or permissions but stressed the closeness of the US-Niger relationship.

"The Government of Niger and the US stand firm in working together to prevent terrorist organizations from using the region as a safe haven. For operational security reasons, I will not comment on specific military authorities or permissions," Maj. Audricia Harris said.

The New York Times was the first to report Niger's granting of authority to arm drones.

Hundreds of US troops are currently helping to build a new drone base in Niger, at Agadez.

The current base of drone operations is near the main civilian airport in the capital, Niamey.