US pilots need to beware of flying too low and scaring walruses forced onto land in northern Alaska by global warming, the Federal Aviation Administration said Tuesday.

The FAA said that the decline in sea ice in the Arctic region of the Chukchi Sea is forcing female walruses and their young to "haul out" to land at times.

But that can put them under the flight paths in the area, and local people have shown concern about how the aircraft could frighten them.

People have expressed concerns "that low-flying aircraft could cause walruses to stampede and kill their pups or harm humans," the agency said.

While the FAA will not set flight path or altitude restrictions on pilots, it said that it will work to inform pilots of the locations of the haul-outs, and reminded that it is against the law to harass walruses.

In recent years scientists have found a number of areas where thousands of walruses amass on coastal beaches, rather than pass their time foraging for food on sea ice.

Last year about 35,000 piled into one site near Point Lay on the Chukchi Sea.