TORONTO – Though many view Canada as an unassuming neutral nation that has skirted terrorist attacks, it has suffered its share of aggression, and intelligence officials believe at least 50 terror groups now have some presence here.

They are from Sri Lanka, Kurdistan and points between and include supporters of some of the best-known Mideast groups, including al-Qaida, authorities say.

Osama bin Laden named Canada one of five Christian nations that should be targeted for acts of terror. The others, reaffirmed last year by his al-Qaida network, were the United States, Britain, Spain and Australia.

The Canadian Security Intelligence Service, counterpart of the CIA, said terrorist representatives are actively raising money, procuring weapons, “manipulating immigrant communities,” and facilitating travel to and from the United States and other countries.

Besides al-Qaida, those groups include Islamic Jihad; Hezbollah and other Shiite groups; Hamas, the Palestinian Force 17, Egyptian Al Jihad and other Sunni groups from across the Middle East, CSIS said.

CSIS said the Irish Republican Army, Tamil Tigers and Kurdistan Workers Party, or PKK, and major Sikh terrorist groups also have supporters in Canada.

The Air India bombing of 1985 was the deadliest terrorist attack on a commercial airliner before Sept. 11, with the government accusing Sikh terrorists living legally in Canada of taking down the airliner over Ireland, claiming 331 lives, most Canadian.

The separatist Tamil Tigers of Sri Lanka – whose followers helped start the trend in suicide bombings when they assassinated Indian Prime Minister Rajiv Gandhi in 1991 – have their political headquarters in a Toronto suburb.

Canada’s clandestine Communications Security Establishment, which listens in on conversations and translates messages from foreigners under suspicion, has increased its annual budget by 57 percent since Sept. 11, and Canada has spent some $6.5 billion to beef up security along its border.

There are now four Arab Muslim men in Canadian jails under “security certificates,” which allow Ottawa to detain suspects without public trial or evidence in the name of national security. All four suspects argue that they face risk of torture if returned to their native Algeria, Morocco, Syria and Egypt. A fifth suspect, Adil Charkaoui, was granted conditional release in February but must wear an electronic tracking device and remain in Montreal. Human rights groups have condemned Canada for holding the men.

Canada adopted its Anti-Terrorism Act in the months after Sept. 11, yet only one man has been arrested under the act: Mohammad Momin Khawaja.

Born in Canada to Pakistani immigrants, Khawaja was arrested in March 2004 on suspicion of participating in and facilitating terrorist activities in London and Ottawa, according to the Royal Canadian Mounted Police.

Young men like Khawaja, 26, are representative of the type of recruits al-Qaida is after, CSIS said in a report recently made public by the Toronto Star.

“There is a direct threat to Canada and Canadian interests from al-Qaida and related groups,” CSIS said. “Converts are highly prized by terrorist groups for their familiarity with the West and relative ease at moving through Western society.”

The U.S. State Department has estimated there are 40 terrorist organizations with sympathizers or supporters in the United States.

AP Homeland Security writer Lara Jakes Jordan contributed to this report from Washington.