Military sources say the soldiers may have drowned while trying to escape from the terrorists' overwhelming attack.
The soldiers were unaccounted for after Boko Haram terrorists attacked their base in Gashigar village, Borno state, on October 17.
According to Premium Times, which cited top military sources, as at Friday October 21, four days after the attack, the soldiers were still missing in action.
The Nigerian Army had confirmed the attack in a statement last Tuesday but did not admit 83 soldiers were missing.
In the statement, Army spokesman Col. Sani Usman simply said some soldiers were missing and 13 injured in the attack.
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Military sources say dozens of the soldiers may have drowned after jumping into the Niger River while fleeing from a superior firepower from the terrorists.
About 22 of the soldiers, who were seriously injured, were said to have been rescued by their colleagues and taken to a hospital in Diffa town, Borno.