(Adds comments, details) By Louise Egan and Tabassum Zakaria MONTEBELLO, Quebec, Aug 20 (Reuters) - U.S. President George W. Bush and leaders of Canada and Mexico sought on Monday to bolster economic and security ties as they met in a Quebec chateau, but a hurricane heading toward Mexico disrupted the summit's schedule. Dubbed the "Three Amigos summit," the meeting of Bush, Canadian Prime Minister Stephen Harper and Mexican President Felipe Calderon is aimed at building on the trade relationship among the partners in the North American Free Trade Agreement. But soon after he arrived at the resort, Calderon announced he would cut his visit to Canada short to return home on Tuesday as the potentially catastrophic Hurricane Dean was bearing down on the Yucatan Peninsula. Dean killed 11 people as it blasted through the Caribbean islands. Late Monday, it strengthened into a monster Category 5 -- the strongest type of hurricane. Bush told Calderon that the United States was willing to assist Mexico with the response to the storm. "We want to be in a position to help them as appropriate and as best we can should Dean hit any part of Mexico," said Dan Fisk, a White House adviser on Western hemisphere affairs. The leaders shifted a lunch meeting set for Tuesday to a breakfast session and moved up their news conference by 1-1/2 hours to noon EDT (1600 GMT). Calderon canceled earlier plans for a meeting with Harper in Quebec's Gatineau Hills on Wednesday as well as a business lunch in Toronto. As the summit in the luxurious cedar chateau got under way, more than 2,000 protesters descended on the village of Montebello, clashing with police in riot gear and decrying what they said was the secrecy of the meetings. Canada and Mexico have been frustrated that trade flows within North America have been hampered by the U.S. crackdown on border security after the Sept. 11 attacks in 2001. To try to tackle that problem, the countries have developed the Security and Prosperity Partnership, or SPP. PROTESTS But protesters said the talks were being carried out behind the backs of ordinary citizens and without any votes planned in the Canadian parliament or U.S. Congress. They also criticized plans for consultations with corporate leaders. Demonstrators banged drums and called for Bush to go home. One group hurled rocks, bottles and cans at police, who fired tear gas. Four people were arrested. "I particularly oppose war criminal Bush seeking to annex Canada and Mexico, to put the armed forces and police services under U.S. command. It's all very dangerous," said Dean Lawveri, 39, of New York state. His comment reflected one theme of the protests -- the worry that national sovereignty will be eroded by the push to boost economic ties and forge a common approach to preventing terrorist attacks. Many Canadians object to what they view as overly harsh U.S. approach to fighting terrorism, including the U.S. detention center at Guantanamo Bay, Cuba. Harper shrugged off the protests. "I've heard it's nothing. A couple hundred? It's sad," he said just before leading Bush into the log-cabin resort. Bush and Harper discussed Canada's mission in Afghanistan, where Canada has 2,600 troops committed through February 2009. Harper appears to have resigned himself to pulling out the troops then since opposition parties, which have more seats in parliament than Harper's Conservatives, oppose an extension. "The prime minister affirmed that Canada would continue with its current mission through February of 2009," Fisk told reporters, adding that "at some point the prime minister will need to go back to parliament to have a decision on what the mission will be beyond February 2009." (With reporting by Caren Bohan and Randall Palmer in Ottawa and Alister Bell in Mexico City)
