WASHINGTON

US fighter jets intercepted two pairs of Russian bomber aircraft off the Alaskan coast for the second time within a week, North American Aerospace Defense Command (NORAD) said in a statement Wednesday.

Two F-22 Raptors, backed by a refueling plane and an early warning aircraft, intercepted two separate formations of Russian aircraft Tuesday night, NORAD said.

The first consisted of two Tu-95 bombers, accompanied by two Su-35 fighter jets, as well as a Russian early warning aircraft while the second was comprised by two Tu-95 bombers supported by an early warning aircraft.

The Russian planes came within 36 miles (58 kilometers) of Alaska, but remained within international airspace, NORAD said.

“For the eighth time this year, Russian military aircraft have penetrated our Canadian or Alaskan Air Defense Identification Zones and each and every time NORAD forces were ready to meet this challenge,” NORAD Commander Gen. Terrence O’Shaughnessy said in a statement.

NORAD sent back two Russian formations early last Wednesday. Those closed to within 23 miles (37 kilometers) of Alaska's shores.

NORAD is a binational command operated between the US and Canada.