Six Russian warplanes were intercepted off the coast of Alaska last week, the latest in a series of incidents involving Russian aircraft in foreign airpsace.

American and Canadian fighter jets intercepted the Russian jets - one group on Wednesday and another group on Thursday - as they entered air space known as the Air Defense Identification Zone off the coast of Alaska, the BBC reported.

"Two Alaskan based F-22 fighter jets identified and intercepted two Russian IL-78 refuelling tankers, two Russian Mig-31 fighter jets and two Russian Bear long-range bombers in the ADIZ, west of Alaska," reads a joint statement from U.S. and Canadian defense officials, the Agence France-Press reported.

The Russian fighter jets did not enter U.S. airspace, which extends 12 nautical miles from land. They left the airspace without incident.

Russian warplanes have been seen in the area before, but last week's interception was "the first time in a long time," reads the statement. The incident has not been perceived as a threat.

Another two Russian fighter jets were also caught Wednesday entering Swedish airspace over the Baltic Sea. Sweden's Foreign Ministry said the incident was a "serious violation" and summoned the Russian ambassador, according to the BBC.

The incident comes less than three weeks after Canadian defense officials accused several Russian military planes of making a "provocative" pass over its navy vessel that was participating in a NATO-led exercise in the Black Sea. Canada said that while no one was injured, the move was "unnecessary."

Russia, currently facing scrutiny from the West for its involvement in Ukraine, denied any of their aircraft approached the foreign vessel.

It is not clear if Moscow has responded to the latest incidents. Russia has referred to such flights in the past as training sessions, according to AFP.