Two groups of Russian maritime reconnaissance aircraft entered the Alaskan Air Defence Identification Zone on Saturday, the US Department of Defence said.
"The Russian aircraft remained in international airspace North of Alaska and at no time did the aircraft enter sovereign United States or Canadian airspace," the North American Aerospace Defense Command (NORAD), which identified the Russian aircrafts, said in a statement on Saturday.
The NORAD is a bi-national command focused on the defense of both the US and Canada.
Identification and monitoring of aircraft entering a US or Canadian ADIZ demonstrates how the NORAD executes its aerospace warning and aerospace control missions for the United States and Canada, the media statement said.
The NORAD employs a layered defense network of radars, satellites, as well as fighters to identify aircraft and determine the appropriate response.
"The NORAD is committed to the defense of the United States and Canada and stands ready in our role of detecting, tracking and identifying aircraft approaching the US and Canadian airspace," said Gen Terrence J O'Shaughnessy, the NORAD Commander.