The town, which has been hit several times by militants, lies on the border of Borno and Yobe states. Borno is the heartland of Boko Haram's six-year insurgency, which aims to carve out an Islamic state.
Ngamdu is about 100 km (60 miles) east of Borno state capital Maiduguri and about 40 km west from Yobe state capital Damaturu, and lies near a road that is a major transport artery between the two states.
A security source said the casualties and wounded were mainly bus and truck drivers. Around six drivers died, he said.
"They came back later on horse, shooting at people. Many were killed and some of our drivers were injured," he said.
Three drivers and some passengers were hit by bullets and being treated in a Maiduguri hospital, Abdullahi said.
This is the second time in a week that militants have hit towns along this road.
Two suicide bombers blew themselves up at a checkpoint at Beneshiek on Saturday, witnesses and a member of the civilian joint task force working with the government said.
With help from Chad and Niger, Nigeria has recaptured several key towns in the last few weeks and Boko Haram has been largely pushed out of Adamawa and Yobe states. On Monday, Chadian and Nigerien troops freed the towns of Malam Fatouri and Damasak from militant control.
Until recently, the insurgents controlled an area the size of Belgium.Güncelleme Tarihi: 10 Mart 2015, 17:37