Motorbikes have been banned from the northern Nigerian city of Maiduguri to prevent drive-by attacks by the radical Islamist sect, Boko Haram.
Officials said no-one would be able to ride motorbikes at any time in the city, Boko Haram's stronghold.
The group's trademark has been to use gunmen on motorbikes to assassinate security officers and politicians.
Boko Haram is fighting for Islamic rule and has rejected talks with the government.
At least 40 people have been killed in Maiduguri, the main city in Borno state, in the past two weeks in attacks blamed on the group.
Last month, the group said it had carried out an attack on the headquarters of the Nigerian police in the capital, Abuja, which killed at least six people.
The Borno state government said it was now imposing a 24-hour ban on motorbikes in the city.
"The ban includes private as well as commercial motorcycles of all categories that operate within Maiduguri metropolis," Usman Ciroma, spokesman for the Borno state governor, said in a statement.
Correspondents say motorbikes are one of the most common forms of transport in Maiduguri, as most people cannot afford cars.
The AFP news agency reports that the governor, Kashim Shettima, warned that the ban could be extended.
"If the security situation does not improve following this ban, the government will extend the ban to cover the whole state," he was quoted as saying.
On Wednesday, Boko Haram fighters threw an explosive device at a military patrol in Maiduguri, wounding three officers.