PARIS -- The heads of state of five West African countries, including Nigeria, met Saturday with Western officials and agreed to share intelligence and strengthen military cooperation to combat the regional threat from the extremist Islamist group Boko Haram, which abducted more than 200 schoolgirls in northern Nigeria last month.
At the request of Nigeria's president, Goodluck Jonathan, President Francois Hollande of France organized the meeting, which was also attended by the heads of state of Cameroon, Niger, Chad and Benin, countries that border Nigeria and that have long been suspicious of one another. The borders among the countries are notoriously porous, and Boko Haram's adherents have easily slipped across them.
"We are here to declare war with Boko Haram," Cameroon's President Paul Biya told journalists at the end of the summit.
Boko Haram has ample funds, highly sophisticated weaponry and advanced training with some of the world's most experienced terrorists, the French president said Saturday as he and African leaders grappled with how to deal with the terrorist group whose dreadful reach was on display this weekend.
Hours after two more attacks in Boko Haram strongholds -- one in Nigeria that left a village torched and 40 people dead and another in Cameroon -- the leaders agreed to improve policing of frontiers and trace the weapons and cash that are the group's lifeblood.
At the summit in Paris intended to hammer out a plan to find and free 276 schoolgirls being held hostage by Boko Haram, intelligence officials from the U.S., Europe and Africa shared information while heads of state and top diplomats tackled policy.
"This group is armed, with heavy weapons of an unimaginable sophistication and the ability to use them," said Mr. Hollande.
He said the weapons came from chaotic Libya, and the training took place in Mali before the ouster of its al-Qaida linked Islamist leaders. As for the money, Mr. Hollande said its origins were murky.
"Boko Haram is acting clearly as an al-Qaida operation," said Mr. Jonathan, who had only reluctantly accepted outside help after years of insisting the group was an internal Nigerian problem.
The five countries agreed to a plan focusing on enhanced military cooperation and intelligence sharing. This would be particularly important between Nigeria and Cameroon, two oil-rich countries whose relationship has long been undermined by a territorial dispute. Cameroon has largely overlooked the activities of Boko Haram, viewing the movement "as Nigeria's problem," according to Le Figaro, a right-leaning French newspaper.
The attack late Friday against a Chinese engineering firm's camp in Cameroon left at least 10 people missing and one person dead. China is a major investor in the region, helping build infrastructure, public health projects and sports facilities and importing crude oil, timber and cotton.
The camp was in the same nearly trackless parkland where the girls were first spirited away after an attack on their school in northern Nigeria, highlighting Boko Haram's ability to cross borders unimpeded.
An intelligence cell involving French, British and American agents is already operating out of Nigeria, but Boko Haram has seemingly continued to strike unimpeded.
Suspected Islamic militants attacked another northeast village before dawn on Saturday, killing about 40 people and burning all the huts as well as three vehicles, according to a member of a vigilante group that went to the village, Dalwa-Masuba, about 50 miles southwest of Maiduguri, the Borno state capital in northeast Nigeria. He spoke on condition of anonymity because his group, one of many vigilante organizations set up to fight Boko Haram, does not permit members to talk to reporters.
Mr. Hollande also emphasized that Boko Haram had clearly established ties with other terror groups in Africa, making it a concern throughout the continent and beyond.
That could provide an opening for U.N. sanctions against the group to freeze its assets and impose travel bans against members. Wendy Sherman, a U.S. diplomat who was at Saturday's talks, said the sanctions could come as soon as next week.
"I can't imagine any country which would not support this designation," she said.
Surveillance jets have joined the search and Mr. Hollande left open the possibility that French fighter jets could be deployed.
Boko Haram has offered to exchange the captive girls for jailed insurgents, while threatening otherwise to sell them into slavery.
Officials have said there will be no Western military operation. British officials say Jonathan has ruled out swapping prisoners for the girls.
"There are many ways to bring this horrific situation to a close, but when and if we know where they are then the Nigerians will have to decide how to proceed," Ms. Sherman said.
Signs are growing that some Nigerian troops are near mutiny, complaining they are overwhelmed and outgunned by Boko Haram. Soldiers have told The Associated Press that some in the ranks actually fight alongside the group. Last year, Mr. Jonathan said he suspected that Boko Haram members and sympathizers had infiltrated every level of his government and military, including the Cabinet.
That complicates attempts to share intelligence. The U.S., France and Britain have all sent experts to help find the girls, but French and American officials have expressed concerns about how any information might be used.
The northeastern region where the girls were kidnapped has suffered five years of increasingly deadly assaults by Boko Haram. Thousands have been killed, including more than 1,500 civilians this year.
Mr. Hollande's administration successfully negotiated the release of French citizens held by Boko Haram -- most recently a family of seven and a priest -- and officials in Paris said France's experience dealing with the group as well as its good relations with the governments concerned were the impetus for the summit.
The New York Times, Associated Press and DPA contributed.