US Air Force and Canadian fighter jets were scrambled to escort two Russian bombers that were travelling in the Arctic region near the North American coastline.
China's air force has landed bombers on islands and reefs in the South China Sea as part of a training exercise in the disputed region, it said in a statement.
The long-range Tupolev Tu-95 bombers were "intercepted and visually identified" on Friday morning by a pair of F-22 Raptors as the Russian aircraft flew just north of Alaska's Aleutian islands.
Suicide bombers killed seven people and wounded 12 in an attack on a power plant north of Baghdad on Saturday, an Iraqi security official said.
Russian bombers based in Iran on Tuesday struck militant targets inside Syria, the Russian Defence Ministry said, after Moscow deployed Russian aircraft to an Iranian air force base to widen its campaign in Syria.
Belgian media which earlier reported the arrest on Wednesday of a prime suspect in Tuesday's bomb attacks in Brussels said the person detained was not, in fact, Najim Laachraoui.
World leaders united in condemning the carnage in Brussels and vowed to combat terrorism, after Islamic State bombers killed around 35 people in a strike at the symbolic heart of the EU.