Washington, Oct 27 (IANS): A US Army team that was ambushed in Niger was gathering intelligence on a terrorist leader operating in the area before it was attacked, military officials told CNN.

Four US and five Nigerien soldiers were killed and two Americans were wounded in the October 4 attack.

The officials told CNN on Thursday said the unit was not under orders to conduct a kill or capture mission on the leader.

Such missions are typically reserved for other elite special operations forces teams.

US authorities have codenamed the target, a regional terror planner and coordinator, "Naylor Road", according to a US senior military official.

The high-value target is also believed to have been involved in attacks in Burkina Faso, the official added.

The 12-man Green Beret-led team was given several different tasks before it was ambushed.

The team's primary mission was to train, advise, and assist a larger Nigerien force of 30 soldiers, CNN reported.

The new details comes a day after Joint Chiefs of Staff Chairman Joseph Dunford told reporters that the troops were on their way back to their operating base when they were ambushed by 50 Islamic State (IS) fighters.

The IS-affiliated attackers used mortars, rocket-propelled grenades, technical vehicles and heavy machine guns.

"My judgment would be that that unit thought they could handle the situation without additional support," Dunford said.

"And so, what we'll find out in the investigation (is) exactly why it took an hour for them to call."