* Two men charged with plot to derail passenger train
* Plot "al Qaeda-supported", not related to Boston bombings
* U.S. officials say pair targeted Canada-U.S. train
By Euan Rocha and Alastair Sharp
TORONTO, April 23 (Reuters) - Canadian police have arrested two men and charged them with plotting to derail a Toronto-area passenger train in an operation that they say was backed by al Qaeda elements in Iran.
"Had this plot been carried out, it would have resulted in innocent people being killed or seriously injured," Royal Canadian Mounted Police official James Malizia told reporters on Monday.
The RCMP said it had arrested Chiheb Esseghaier, 30, of Montreal, and Raed Jaser, 35, of Toronto in connection with the plot. Authorities said it was not linked to last week's Boston Marathon bombings, which killed three people and injured more than 200.
Neither suspect is a Canadian citizen, and police did not reveal their nationalities. Two sources following the investigation said one was Tunisian.
Canada's intelligence agency has long expressed concern about the possibility that disgruntled and radicalized Canadians could attack targets at home and abroad.
Police gave little detail about the alleged plotters, but said a tip from the Muslim community had helped their year-long investigation.
Esseghaier has been a doctoral student at the Institut National de la Recherche Scientifique near Montreal since 2010 and was about midway through his degree, the school said.
"He is doing a PhD in the field of energy and materials sciences," Julie Martineau, the school's director of communications, told Reuters.
A bail hearing for the two men was due to take place in Toronto on Tuesday morning.
Malizia said they had received "support from al Qaeda elements located in Iran" but there was no indication that the plot, which police described as the first known al Qaeda-backed plot on Canadian soil, was sponsored by the Iranian state.
Al Qaeda is strongly Sunni Muslim-oriented. Shi'ite Iran did host some senior al Qaeda figures under a form of house arrest in the years following the Sept. 11 attacks, but there has been little to no evidence to date of joint attempts to stage attacks against the West.
However, a U.S. government source said Iran was home to a little-known network of al Qaeda fixers and "facilitators" based in the Iranian city of Zahedan, very close to Iran's borders with both Pakistan and Afghanistan.
The source said they serve as go-betweens, travel agents and financial intermediaries for al Qaeda operatives and cells operating in Pakistan and moving through the area.
They do not operate under the protection of the Iranian government, which periodically launches crackdowns on al Qaeda elements, though at other times it appears to turn a blind eye to them.
It is also an area where Iranian authorities have battled a Sunni insurgency of their own in recent years. The Sunni group Jundollah is alleged to have carried out several attacks including a bombing that killed 42 people in 2009, and attacks on mosques in Zahedan.
U.S. officials said the attack would have targeted a rail line between New York and Toronto, a route that travels along the Hudson Valley into New York wine country and enters Canada near Niagara Falls.
Canadian police said only that the plot involved a VIA train route in the Toronto area.
New York Police chief spokesman Paul Browne told Reuters that the NYPD had been kept informed of the investigation from "early on."
Malizia said the RCMP believed the two suspects had had the capacity and intent to carry out the attack, but there had been no imminent threat to the public, passengers or infrastructure.
The plot is one of a handful of terrorism-related investigations involving Canadians or Canadian residents.
Police said earlier this year that Canadians had taken part in an attack by militants on a gas plant in Algeria in January, while Canadian and Somalia authorities are investigating whether a former University of Toronto student participated in a bomb attack in Mogadishu last week.
And in 2006, police arrested and charged nearly 20 Toronto-area men accused of planning to plant bombs at various Canadian targets. Eleven were eventually convicted.
"Today's arrests demonstrate that terrorism continues to be a real threat to Canada," Public Safety Minister Vic Toews told reporters in Ottawa.
"Canada will not tolerate terrorist activity and we will not be used as a safe haven for terrorists or those who support terrorist activities."