The Nigerian army says it has killed seven suspected members of the Islamist militant group Boko Haram in a gun battle in the north of the country.
A spokesman said a further 13 people were arrested after an attack on an army checkpoint in Maiduguri.
Earlier, Nigerian police said they would mount a 24-hour guard of mobile-phone installations following Boko Haram attacks on masts in the north.
Boko Haram said it believed the masts were being used to track its members.
Giving details of the incident in Maiduguri, Lt Col Sagir Musa said: "A group of gunmen suspected to be Boko Haram terrorists opened fire on a military checkpoint where soldiers were conducting a cordon-and-search operation.
"The soldiers responded with gunfire, leading to a shootout. Seven gunmen were killed in the fire exchange and 13 others were arrested while the rest fled. No casualty was recorded on the part of the soldiers."
Boko Haram wants to impose Sharia law across Nigeria.
It launched a military campaign in 2009 to fight for Islamic rule, bombing government buildings and churches, and assassinating moderate Muslim clerics.
The country is roughly divided between a mainly Muslim north and predominately Christian and animist south.