* Says 6,000 troops, police will protect May 7-9 summit
* Monday's bombing on Abuja outskirts killed at least 71
* Military struggling to contain Islamist insurgency
* Jonathan urged to accept foreign help to fight "terrorism" (Recasts with additional quotes, details)
By Felix Onuah and Camillus Eboh
ABUJA, April 15 (Reuters) - Nigeria pledged on Tuesday to deploy more than 6,000 police and soldiers to protect a World Economic Forum on Africa in Abuja next month, a day after a bomb attack by suspected Islamist militants on the capital's outskirts killed dozens.
African heads of state and business leaders are due to attend the May 7-9 WEF event - based on the flagship gatherings in Davos, Switzerland - where Nigeria's government wants to showcase the top oil producer's newly acquired status as the largest economy on the continent.
Monday's bombing at a crowded bus station killed 71 people, the deadliest ever attack on Abuja, and has raised questions about the government's ability to protect the capital from Boko Haram's bloody insurgency that risks spreading from the Islamist group's heartland in the northeast.
Ahead of elections in February, President Goodluck Jonathan is under intense pressure to contain the five-year insurrection.
Boko Haram wants to carve an Islamic state out of a country split between Muslims living largely in the north and Christians mostly in the south, and its fighters have shown that they can strike further south and in the central zone.
Calling Monday's attack a "suspected act of terrorism", Finance Minister Ngozi Okonjo-Iweala said security agencies were "currently in the middle of a robust and thorough investigation to ensure that the perpetrators are brought to justice".
"Our security planning for the World Economic Forum on Africa is already well under way and will be the largest security operation ever mounted in this country for an international summit," she said in a note sent to participants and seen by Reuters, noting that security personnel would secure an area of 250 square kms (100 square miles) around the event.
The statement was also signed by Nwanze Okidegbe, Jonathan's chief economic adviser.
Assuring WEF participants that they would be safe, the note expressed Nigeria's "deep commitment that these tragic events will not stop us from delivering on our promise to host a world-class meeting next month".
Last year's World Economic Forum on Africa was held in Cape Town, South Africa, which Nigeria overtook as Africa's largest economy this month through a rebasing exercise that expanded its GDP to nearly $510 billion in 2013.
NIGERIA URGED TO ACCEPT FOREIGN HELP
Visiting the scene of the bombing at Nyanya on Monday, Jonathan implored Nigerians to be more vigilant and called the threat from Boko Haram "temporary".
But, despite a state of emergency declared last year in the northeastern states and a muscular offensive involving thousands of troops backed by aircraft, Nigeria's military has failed to quell the revolt.
Former Vice President Atiku Abubakar, a northern politician who defected to Nigeria's main opposition in February from Jonathan's ruling People's Democratic Party (PDP), urged the government to accept foreign help in fighting what he called "terrorism".
"There is an urgent need for the government of Nigeria to review its methods and strategies for dealing with terrorism," Abubakar said in a statement that called on Jonathan's administration to use increased and improved intelligence methods to detect and pre-empt attacks by Boko Haram.
"As a country, we are not doing enough of focusing on and implementing solutions," Abubakar said.
Boko Haram militants are increasingly targeting civilians they accuse of collaborating with the government or security forces. Security sources estimate the conflict has killed more than 2,000 people in the past six months alone.
The United States condemned Monday's bombing and said it stood with Nigerians as they grapple with "violent extremism".
There had been no violence on such a scale near the capital since suicide car bombers targeted the offices of the newspaper This Day in Abuja and the northern city of Kaduna in April 2012.
A Christmas Day bombing of a church in Madalla, on the outskirts of Abuja, killed 37 people in 2011. Boko Haram also claimed responsibility for a bomb attack on the United Nations' Nigeria headquarters that killed 24 people on Aug. 26, 2011.
Boko Haram, which in the Hausa language means broadly "Western education is sinful", is loosely modelled on the Taliban movement in Afghanistan, and has forged ties with al Qaeda-linked militants in the Sahara. (Additional reporting by Tim Cocks in Lagos and Pascal Fletcher in Johannesburg; Writing by Pascal Fletcher; Editing by Louise Ireland)