* Will share intelligence, patrol jointly, monitor borders
* Nigeria says Boko Haram now West African al Qaeda
* Abuja likely to refer group to U.N. Security Council
* Attack on Chinese site in Cameroon shows regional threat (Recasts with quotes, conclusions)
By John Irish and Elizabeth Pineau
PARIS, May 17 (Reuters) - West African leaders on Saturday agreed to work together to wage "total war" on Boko Haram saying the Nigerian Islamist group had become a regional al Qaeda that threatened all of them.
Nigeria's neighbours Chad, Cameroon, Niger and Benin, and Western officials, met in Paris to flesh out a plan enabling them for the first time to share intelligence, coordinate action and monitor borders.
Although Boko Haram has been fighting for five years, carrying out bombings and attacks on civilians and the security forces, the kidnapping last month of more than 200 girls from a school in the northeast has focused world attention on them.
"Boko Haram is no longer a local terrorist group, it is operating clearly as an al Qaeda operation, it is an al Qaeda of West Africa," Nigerian President Goodluck Jonathan told a news conference in Paris following the meeting.
"We have shown our commitment for a regional approach. Without West African countries coming together we will not be able to crush these terrorists," he said.
Outrage over the mass abduction has prompted Nigerian President Goodluck Jonathan - criticised at home and abroad for his government's slow response - to accept U.S., British and French intelligence help in the hunt for the girls.
British Foreign Minister William Hague, speaking before the start of a meeting, said the Nigerian military was not organised in a way to deal effectively with the group, and offered military advisers to help structure them.
"There is determination to tackle this situation head on ... to launch a war, a total war on Boko Haram," Chad's President Idriss Deby said.
The countries agreed to launch coordinated patrols and rescue operations, share intelligence, put in place a mechanism to prevent weapons' smuggling and monitor borders.
Intelligence services and army heads would also meet soon to come up with a region-wide strategy to fight terrorism.
"The threat is serious and dangerous for the region, Africa and Europe," French President Francois Hollande said, although no concrete operational measures were announced.
With 6,000 French troops operating in either Mali to the northwest or the Central African Republic to the east, Paris has an interest in preventing a deterioration in Nigeria's security.
Like its Western allies, Paris has ruled out any military operation saying it was primarily for Nigeria to take the lead, although Hollande said Rafale fighter jets based in the Chadian capital N'Djamena - just 60 km from the Nigerian border - would be used for reconnaissance missions.
Paris fears Boko Haram could spread north into the Sahel and beyond Cameroon into the Central African Republic. Boko Haram has already targeted French interests in Nigeria, kidnapping a French family in northern Cameroon last year.
Suspected Boko Haram rebels also attacked a Chinese work site in northern Cameroon on Friday, killing at least one Cameroonian soldier, and at least 10 people are believed to have been kidnapped, the regional governor said.
"We have affirmed our solidarity and determination to vigorously fight Boko Haram," Cameroon President Paul Biya said. "They have committed one more attack, attacked businessmen and this comes after the French hostages were kidnapped. As we speak we are searching for an Italian priest and a Canadian nun. The problem has become regional, if not a Western problem."
The group has killed more than 3,000 people in its war to establish an Islamic state in mostly Muslim northeast Nigeria.
Biya said he would send more means and troops to the north, but that Boko Haram had been picking soft targets and outnumbering his troops.
Nigeria has complained the far north of Cameroon is being used by Boko Haram militants to shelter from a Nigerian military offensive and to transport weapons, and has urged Cameroon to tighten border security.
Jonathan said there was a "misconception" in the relation between the two countries over crossing each others borders and that this would now be ironed out.
"The main outcome is that the region is now aware of a problem that for a long time was considered an internal Nigerian problem. Abuja has accepted to go beyond its borders," a Western diplomatic source said.
Highlighting that, the source said Nigeria, which sits on the 15-member U.N. Security Council, had agreed in principle to ask for Boko Haram and its key members to be placed on a U.N. sanctions list, as has been the case with other militant groups such as al Qaeda.
"The world is aware of these young school girls who were abducted, but quite frankly Boko Haram has been creating havoc for sometime," U.S. Under Secretary for Political Affairs Wendy Sherman told Reuters.
"We are all coordinated, we are all focused, this doesn't stop at borders, terrorism does not know borders and so we're going to work in a collective manner to get the job done." (Editing by Alison Williams)