* Series of dawn raids sweeps up suspected Boko Haram members
* Islamists are Nigeria's top security threat
KANO, Dec 9 (Reuters) - Nigerian security forces said they arrested 28 suspected members of Islamist sect Boko Haram over the weekend, in a series of dawn raids on their hideouts.
"Our plan is to choke the (militants), to suffocate them and we are getting the desired results," said a spokesman for joint military and police forces in Kano, Lieutenant Ikedichi Iweha.
Boko Haram has become the main security threat to Africa's leading energy producer.
Human Rights Watch says at least 2,800 people have died in fighting in the largely Muslim north since the sect launched an uprising against the government in 2009 in a bid to impose sharia law on Nigeria.
Much of the fighting in the north has centred on the city of Maiduguri.
Kano, Nigeria's second biggest city, has been quiet by comparison in the latter half of this year, although it remains a trouble spot. In January, it was scene of the single deadliest attack of the insurgency, a coordinated strike on several police stations in which 186 people were killed, many of them civilians.
Eight suspected Islamists were arrested in Kano on Thursday after police said they threw an improvised bomb at a police patrol vehicle but missed. (Reporting by Chukwuemeka Madu; Writing by Tim Cocks; Editing by Myra MacDonald)