LOS ANGELES, Jan 8: Hundreds of undocumented Pakistanis and Arabs, many of whom have lived in the United States for years, have crowded Canadian border crossings in recent days to seek asylum as America cracks down on illegal immigrants as part of its war against terrorism.

The surge at crossings in Quebec, Ontario and, to a lesser extent, British Columbia, appears to reflect mounting fear among foreigners without legal status in the United States, particularly those of Middle Eastern, South Asian, and North African origin, that they now face a greater risk of being deported from the United States.

The startling exodus also appears to reflect widening alarm among the immigrants about a new US-Canada anti-terrorist accord that will require Canada to raise stronger barriers to refugee claimants arriving from the United States.

Under the “smart border” agreement reached between Ottawa and Washington last month, refugee claimants who arrive at Canadian entry points from the United States will, in most cases, automatically be turned back and forced to take their chances under the stricter US system. No firm date has been set for implementing the agreement, but it could take effect as early as spring.

In 2001, Canada received 44,713 people claiming to be refugees, including 13,493 “third country” nationals who entered by way of the United States, according to Canada’s Ministry of Citizenship and Immigration.

Jean Cheney, a spokesperson for the immigration ministry, said nearly 250 people — mainly of Pakistani origin — have sought entry as refugees at the border crossing near Lacolle, Que., on the main route between New York City and Montreal, in the past week.