(Reuters) - Nigeria's army killed 11 suspected Boko Haram insurgents during a gun battle at a checkpoint in the Islamist sect's heartland of Maiduguri on Saturday, the field operations officer in the remote northeastern city said.

Nigerian forces are reeling from a sharp uptick of increasingly sophisticated and coordinated attacks by Boko Haram. Human Rights Watch says it has killed hundreds of people since launching an uprising against the government in 2009, including an attack on the city of Kano that killed 186.

"Eleven BH (Boko Haram) members have been shot dead by the JTF (joint military taskforce) in Maiduguri today, following a shootout with the sect members at a checkpoint in a stop and search operation," field operations officer Colonel Victor Ebhamelehe said told Reuters.

"One member of the sect who was wounded is receiving treatment at the hospital."

Boko Haram began as a clerical movement opposed to western cultural influences in Maiduguri, a dusty town in the northeast region bordering Chad, Niger and Cameroon, on the cusp of the Sahara. It has since spread to much of Nigeria's north and has become the top security threat in Africa's biggest oil producer.

Suspected sect members attacked a police station in Mandwari, in north Nigeria's Kano state, on Friday, police and witnesses said, leading to more than an hour of running gun battles that fatally wounded one policeman.

"We lost one of our men in the attack in Mandwari inside the city. He is a corporal and he died on the way to hospital. The gunmen were repelled," Kano police commissioner Ibrahim Idris told Reuters on Saturday.

In an audio tape posted on the Internet on Thursday, the purported leader of Boko Haram, Abubakar Shekau, threatened to kill more security personnel and kidnap their families, and accused U.S. President Barack Obama of waging war on Islam, in an apparent effort to strike a chord with global jihadists.

He denied that the group, which is loosely modelled on the Taliban, had been responsible for most of the civilian casualties in last Friday's attack on Kano. Police say most of those casualities were shot dead by sect members.

(Reporting by Ibrahim Mshelizza; Additional reporting by Mike Oboh in Kano; Writing by Tim Cocks; Editing by Alison Williams)

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