Maiduguri - Nigerian troops moved into cities in the northeast on Wednesday, after President Goodluck Jonathan declared a state of emergency there in response to an Islamist insurgency.
Residents and Reuters reporters saw army trucks carrying soldiers enter Yola and Maiduguri after Jonathan declared the emergency on Tuesday in three states - Borno, Adamawa and Yobe - following attacks by militants of Boko Haram.
Military officials in the northeast and at headquarters in Abuja were not immediately available for comment.
A Reuters reporter saw six trucks carrying soldiers enter Yola, capital of Adamawa state. In the Borno state capital Maiduguri, the biggest city in the area and birthplace of the insurgency, residents also reported an influx of troops.
The mood was tense in that city. Shops were mostly shut and there were few people on the streets. Schools were closed.
"What I saw this morning scared me," said one man in Maiduguri, Ahmed Mari.
"I have never seen soldiers on the move quite like this before."
Another, Kabir Laoye, voiced widespread fears that civilians could be caught up in the conflict: "There is a lot of apprehension about the state of emergency," he said.
Jonathan announced the move in a televised address on Tuesday, responding to an intensification of attacks on security forces and government targets in the Islamist strongholds in the northeast.
His orders followed growing evidence that Boko Haram now controls substantial territory around Lake Chad, where local officials have fled.
Officials say militants control at least 10 local government districts of Borno state and are using porous borders with Cameroon, Chad and Niger to smuggle in arms and mount attacks.
Dozens of Boko Haram fighters in buses and with trucks mounted with machineguns laid siege to the Borno town of Bama last week, freeing over 100 men from prison and leaving 55 people dead, mostly police and other security personnel.
Two weeks earlier, scores were killed in the fishing village of Baga, on the shores of Lake Chad, when troops from Nigeria, Niger and Chad raided it looking for Islamists who had killed a soldier.
Local residents said soldiers were responsible for many civilian deaths.