MAIDUGURI (Reuters) - Around 70 Nigerian soldiers were killed in an Islamist militant ambush in northeastern state of Borno, three military sources and a security source told Reuters on Tuesday.

They said the attackers used rocket-propelled grenades and other heavy weaponry in the attack in the village of Gorgi on Monday evening. Injured soldiers were brought to the capital city of Maiduguri, while the bodies of the dead were brought to Maimalari military hospital.

Military spokesman Sagir Musa confirmed there was an attack, but disputed the number of soldiers killed. He declined to share other details.

And President Muhammadu Buhari expressed “profound grief and sorrow” at the death of the soldiers in a statement late on Tuesday. But the statement did not refer to a death toll.

It was not immediately clear who the attackers were. Militants from both the Boko Haram and the Islamic State West Africa Province groups are active in the region.