A helicopter has crashed in the Nigerian state of Niger. killing more than two dozen officers, military authorities say.

The evacuation mission had been to retrieve soldiers wounded or killed in an ambush by armed bandits in Chukuba village in the Shiroro local government area of Niger state.

The figures were given by a spokesperson for the Nigerian military, Major General Edward Buba, during a press briefing in Abuja on Thursday. He said there were 14 soldiers and seven wounded ones aboard the aircraft when it crashed, alongside two pilots and two crew members.

Buba said an investigation is under way to determine the cause of the crash.

Authorities have yet to disclose the details of the evacuation mission or any more information about the crash, including whether there were any survivors.

“These officers and men were answering the call of duty while on an evacuation mission. In their dedicated service to our beloved country, they paid the ultimate price,” President Bola Tinubu said in a statement on Tuesday.

“We will forever remember them, not just as servicemen, but as national heroes who gave their all for the peace and security of our country,” Tinubu said.

Local news outlet Leadership reported that the helicopter was evacuating the bodies of security operatives killed by bandits before crashing in Chukuba. The newspaper said sources confirmed the armed men carried sophisticated weapons that could bring a helicopter down.

The helicopter took off from Kaduna Airfield to Minna but lost contact with control towers from both Kaduna and Minna, Leadership reported.

Dogo Gide, the notorious leader of a group of bandits that has been a source of terror across parts of northwestern Nigeria bordering the countries of Niger and Chad, has claimed responsibility for the attack, according to Premium Times, another local outlet.

The warlord, an ethnic Fulani from Niger state, has been linked to Ansaru, a faction of Boko Haram that drifted westwards from the restive northeast.

Al Jazeera could not independently verify the claim at the time of this report.