Published: 2019-09-12 10:20:03 BdST
A decade-long insurgency in the northeast, started by Islamist group Boko Haram in 2009, has claimed more than 30,000 lives. A breakaway faction that pledges allegiance to Islamic State has become the dominant group in the insurgency, carrying out attacks on military bases over the past year.
The soldiers and security officer, all of whom spoke on condition of anonymity, said Islamist militants attacked troops on Tuesday at a military base in Gudumbali - a town in Borno, the state worst hit by the insurgency.
They said nine soldiers were killed in the attack and 27 were missing.
"We repelled the attack," said Nigerian Army spokesman Sagir Musa. He said he was not aware of any soldiers being killed or having gone missing.