U.S. fighter jets intercepted four Russian aircraft entering the Air Defense Identification Zone (ADIZ) near Alaska on Saturday, a signal that military tensions could be increasing between the Pentagon and Moscow. The four Russian Tu-142 reconnaissance aircraft came within 65 miles of the Alaskan Aleutian Islands but did not enter U.S. or Canadian airspace.

The Russian planes stayed in the ADIZ for nearly eight hours. This is the fourth such incident this month in the region.

"This year alone, NORAD forces have identified and intercepted Russian military aircraft including bombers, fighters, and maritime patrol aircraft on ten separate occasions when they have flown into the ADIZ," NORAD commander Gen. Terrence J. O'Shaughnessy said in a statement. “Despite COVID-19, we remain fully ready and capable of conducting our no-fail mission of homeland defense."

NORAD stands for North American Aerospace Defense Command, a combined U.S.-Canadian organization specializing in aerospace and maritime threat detection. On Wednesday, U.S. F-22 jets intercepted two Russian IL-38 maritime patrol aircraft penetrating the ADIZ.

U.S. and Russian relations could be escalating. The New York Times reported Friday that U.S. intelligence concluded months ago a Russian military intelligence unit offered bounties to the Taliban to kill American troops operating in Afghanistan. The Russian Embassy in Washington, D.C., has called the allegations “baseless and anonymous” while the Taliban has denied "any such relations with any intelligence agency."

Russia has frequently sought to undermine U.S. security and the integrity of presidential elections. In 2016, Russia interfered in the U.S. presidential election, boosting the candidacy of then-Republican candidate Donald Trump and harming the campaign of Democratic candidate Hillary Clinton.