The US military unit ambushed in Africa earlier this month didn’t call for support until an hour after the attack — and French jets didn’t reach the scene for another hour, the chairman of the Joint Chiefs of Staff said Monday.

The unit of 12 Special Forces soldiers and Nigerian forces came under fire from ISIS-affiliated terrorists Oct. 4 and “did not call for support until an hour after contact,” said Gen. Joseph Dunford.

“The timeline we have is the first indicator that the unit called for external support until an hour later,” he said, explaining that it’s unclear whether the soldiers felt they were able to handle the attack until they called for help.

“I don’t know that they needed support until that time,” Dunford said. “Our logs indicate that an hour after the contact, they sought support.”

The French finally got the call to intervene after the “difficult firefight” began, and it took them a half-hour to respond.

A half-hour after that, French fighter jets finally arrived, Dunford said.

Most other details of the attack that left four US soldiers dead and two others wounded are still unclear, Dunford said.

Once the investigation is complete, he said, military officials will visit the families of the fallen soldiers and share the information before making it public.

“We owe the families and the US people transparency,” he said.

Dunford acknowledged that there’s a “perception that the Department of Defense has not been forthcoming,” which is why he held the press briefing.

“I thought it would be helpful for me to personally clarify to you what we know today, and to outline what we hope to find out in the ongoing investigation,” he said.

On Oct. 3, a group of 12 American forces traveled to the village of Tongo Tongo, which is about 53 miles north of the capital, with 30 Nigerian forces on a “reconnaissance mission,” Dunford said.

“The assessment by our leaders on the ground at that time was that contact with the enemy was unlikely,” he said.

The next day, the soldiers were moving back to their base when they came under fire from about 50 fighters, believed to be from a local Islamic State affiliate, who attacked them with small arms and rocket-propelled grenades, Dunford said.

Four soldiers — Sgt. La David Johnson, 25, Staff Sgt. Bryan Black, 35, Staff Sgt. Jeremiah Johnson, 39, and Staff Sgt. Dustin Wright, 29 — ​were killed.

Dunford said there’s no indication the soldiers took too many risks.

“I don’t have any indication right now to believe or to know that they did anything other than operate within the orders they were given,” he said.

Dunford defended the broader American mission in Niger, where he said US forces have been stationed intermittently for more than two decades.

He said about 800 troops are there now.