TORONTO, AUG. 21 -- U.S. authorities are attempting to stop illegal aliens from crossing to America on a dangerous Canadian Pacific railway bridge spanning the Niagara Gorge and have threatened to fine the company at least $27,000.

The most recent smuggling attempts have been made in the middle of the night when it is very dangerous to cross, Benedict Ferro, district director of the U.S. Immigration and Naturalization Service in Buffalo, N.Y., said Thursday.

"That bridge represents a major problem in terms of potential loss of life," he said.

Ferro said he issued a notice of intent to fine CP Rail, which owns the bridge, at least $27,000 in connection with 27 illegal immigrants who made the dangerous crossing in groups in the last several months.

Under U.S. immigration law, owners of vessels or bridges are subject to fines of $1,000 for each alien they fail to stop.

CP spokesman Jim Barlow said the railway, Canada's second largest and a division of giant Canadian Pacific Ltd., has never spotted immigrants on the bridge, which runs over the river from Niagara Falls, Ontario, to Niagara Falls, N.Y. But Ferro said it is believed immigrants cross beneath the bridge on its superstructure, a dangerous undertaking even in daylight.