Nigerian soldiers have fought off Boko Haram jihadists in separate attacks, the army and military sources said Monday, as clashes persist while elections approach.
The army said troops "successfully defeated Boko Haram terrorists" who tried to attack a military base in Buni Yadi in Yobe state, northeast Nigeria, on Sunday.
On Saturday, soldiers "inflicted devastating man and equipment casualties" on the group in the Baga area of Borno state, on the shores of Lake Chad, killing five.
Two Islamist fighters were also killed in operations in the Mafa district of Borno, it added in a series of statements.
The government's record on tackling Boko Haram is under increased scrutiny as the country heads to the polls to elect a new president and parliament on February 16.
President Muhammadu Buhari, a former military ruler, was elected in 2015 on a pledge to defeat the group, whose insurgency has killed more than 27,000 since 2009.
He has said Boko Haram is "technically defeated" but attacks have not stopped, and a faction backed by the Islamic State group has increased its strikes on military positions.
Last week, six soldiers were killed when Boko Haram gunmen attacked Kamuya village near the native home of Nigeria's army chief, Lieutenant-General Tukur Yusuf Buratai.
Two military sources said the IS-allied faction -- Islamic State West Africa Province (ISWAP) -- was behind the weekend attacks in Baga, Kareto and Buni Yadi.
The sources both said four soldiers were killed as they repelled the attack in Buni Yadi during "intense" fighting that involved air strikes.
Nigerian troops returned to Baga on January 9 after a wave of ISWAP attacks against two military bases in late December that forced more than 30,000 civilians to flee.
Some 10,000 other people displaced by the conflict were also forced to flee after another attack in the remote town of Rann last week.
The movement has increased pressure on aid agencies providing humanitarian assistance. It has also raised questions about how elections can be held in areas hit by fighting.