* No known attacks by Boko Haram Islamists in Lagos
* Sect has killed thousands in four-year insurgency
* President's peace committee given two-month extension (Adds further government dialogue efforts with Boko Haram)
LAGOS, July 30 (Reuters) - Nigerian authorities have arrested 42 suspected members of Islamist sect Boko Haram in Lagos and the neighbouring southwest state of Ogun, an army spokesman said on Tuesday.
During a four-year insurgency Boko Haram's attacks have been focused mostly in the Muslim north, far from the commercial capital Lagos and the southern oil fields which provide more than 2 million barrels per day to world markets.
The sect, which wants to carve out an Islamic state in the religiously mixed country, has never claimed responsibility or been blamed for an attack in Lagos, Nigeria's biggest city.
"We have arrested 42 suspected members of Boko Haram in Lagos and Ogun," said an army spokesman in Lagos, Kingsley Umoh. "Some have already confessed to being Boko Haram and said they fled the northeast due to the military efforts there."
A military crackdown in Boko Haram's northeast stronghold since mid-May has weakened the group but it has also pushed militants into hiding and security sources fear attacks could spread to other areas.
Multiple bomb blasts in Nigeria's biggest northern city of Kano killed 15 people on Monday in a predominantly Christian area previously targeted by Boko Haram.
President Goodluck Jonathan says he is still open to a peaceful resolution with Islamist rebels and has set up a committee to discuss offering Boko Haram members amnesty in return for laying down their weapons.
But the group's leader Abubakar Shekau has said in several Internet videos that he is not interested in dialogue.
The committee was due to submit its report and recommendations this week but on Tuesday Jonathan extended the deadline by two months.
He said the committee was making progress.
"We are engaged in critical discussions with insurgents ... that will lead not only to the signing of ceasefire agreements ... but also lead to disarmament," chairman of the committee Tanimu Turaki told reporters on Tuesday. (Reporting by Tim Cocks in Lagos and Isaac Abrak in Kaduna; additional reporting by Felix Onuah in Abuja; Writing by Joe Brock; Editing by Elizabeth Piper and Sonya Hepinstall)