OTTAWA, Sept. 11 -- Prime Minister Jean Chretien said Tuesday that "Canada will do everything it can to help" the United States "in this very difficult situation -- an unprecedented crisis."
He was speaking to reporters after an emergency meeting with his Cabinet and security officials in Ottawa.
Chretien said he had been in touch with U.S. authorities and with the Canadian ambassador in Washington, and condemned the attacks in New York and Washington as "unspeakable violence, an offense against the freedom and rights of all civilized nations."
Earlier, commercial planes diverted from New York and other U.S. airports began landing in Canada.
More than 35 landed in Nova Scotia and Newfoundland in the first three hours after the crisis began, while Toronto, Ottawa and other Canadian airports cleared their tarmacs and made preparations to receive more than 100 planes.
In Whitehorse, Yukon Territory, two Korean Airlines planes made emergency landings, apparently after running out of fuel, and the Royal Canadian Mounted Police surrounded the aircraft on suspicion that they had been hijacked.
Chretien said, "Canadians will show their solidarity with our neighbors." The number of people who have died "is probably very tragic, and it's creating a very difficult situation around the world," he said.
Canada would send doctors and other resources to the Untied States to help in the emergency, he said. "We are ready to help those people. There are hundreds, thousands of victims, possibly."
"We don't know how many victims there are, how many are injured, how many in hospital," he said. "Our representatives in New York are keeping us informed of the situation. The same thing for Washington."
Meanwhile, the newly established Canadian blood services said thousands of people were calling to donate blood for American victims, amid reports of a blood shortage in New York and Washington.
Chretien said special security measures had been taken in Canada, but he called on Canadians "to remain calm."
Border crossings between Canada and the United States were put on high security alert, but the borders were reopened in the early afternoon, after being closed for about two hours. However, reporters crossing into the United States said their vehicles were put through unusually thorough searches, and no one was being allowed in unless they had passports or could show birth certificates to prove their identities.
Canadian authorities said they were making special arrangements to accommodate the travelers arriving by plane in Canada, and special buses were brought to the airport to help move them. Some schools were converted into emergency shelters. Most of the arriving passengers had not heard about the attacks in the United States, until after their planes landed.
Canadians who had been booked on flights from Canada were told to stay home, as airports across the country were closed to all but incoming flights, as part of the emergency measures.
Of the attacks in New York and Washington, Chretien said, "It is impossible to fully comprehend the evil that would have conjured up such a cowardly and depraved assault upon thousands of innocent people."
Earlier, he canceled all his activities that had been scheduled for Tuesday. Security was stepped up at his office in Ottawa, and Chretien was moved to an unnamed location. He also canceled a planned flight to Halifax, Nova Scotia. A scheduled meeting with visiting Slovak Prime Minister Mikulas Dzurinda was also canceled.
The RCMP said they had stepped up security measures at government buildings, including the Parliament building, though Parliament had yet not reopened after the summer recess.
The Toronto Stock Exchange closed trading within an hour of the first attack on the World Trade Center buildings in New York, and the exchanges in Montreal, Vancouver and Calgary also closed for the day. There was no immediate word on whether they would reopen on Wednesday. Major banks closed their downtown offices in Toronto, but continued operations in other areas.