Nigerian troops were out on the streets of the volatile northern city of Kaduna on Sunday to prevent any outbreak of violence following the death of the state governor in a helicopter crash.

Kaduna state governor Patrick Ibrahim Yakowa, a former national security advisor Owoye Azazi and four other people were killed when a chopper operated by the navy went down in the south of the country on Saturday on route to the oil hub of Port Harcourt.

The army spokesman in Kaduna, Colonel Sani Usman, confirmed the deployment of troops on the streets of the religiously divided state capital, which has witnessed a spate of clashes between Christian and Muslim residents that have left scores of people dead this year.

"Security is part of the military routine process to secure lives and property and to ensure that people are able to conduct their legal activities without fear," Usman told AFP.

Kaduna state has also been among the hardest hit by radical Islamist group Boko Haram, which has repeatedly used suicide bombers to attack churches in and around the state capital.

Troops and armoured personnel carriers were patrolling Kaduna city, while some major highways were closed to traffic by soldiers manning checkpoints and roadblocks, a local journalist said, and the usually bustling streets were deserted.

Yakowa's deputy Mukhtar Ramalan Yero, a Muslim, is expected to be sworn in on Sunday as the new Kaduna state governor, officials said.

Yero, a close ally of Vice President Namadi Sambo, was a former finance commissioner in the state before he became deputy to Yakowa -- a Christian -- in 2010.

President Goodluck Jonathan has expressed "utter shock and sadness" over the crash and ordered an investigation.