Defence Secretary Ashton Carter promised that the US would deploy state of the art weaponry in Asia, including the latest stealth bombers and cyber warfare units.
NATO allies are scrambling to protect vulnerable Baltic partners from the threat of hybrid warfare, a Russian tactic that officials and experts say is based on deception rather than formal declaration of war.
Estonia's centre-left coalition is poised to return to power in an election marked by nerves in the NATO member over the military resurgence of Russia.
Estonia marked its independence day with a military parade featuring NATO hardware and troops on its eastern border with Russia amid heightened east-west tensions over Ukraine.
Denouncing a business-as-usual approach to Syria, UN chief Ban Ki-moon called for urgent action to lift sieges on civilians and to end barrel bomb attacks.
Ashton Carter was confirmed as US defense secretary, and he could soon find himself at odds with a White House that clashed with previous Pentagon chiefs.
US President Barack Obama agreed to hold off a controversial decision on sending arms to Ukraine until German-led efforts to broker a ceasefire with Russia are given a chance.
NATO defence ministers agreed to immediately set up six bases in eastern Europe and establish a spearhead force of 5,000 troops in response to Russian aggression.
Residents of the Tekstylnyk district in east Ukraine rebel stronghold Donetsk have only tears and unanswered questions after a barrage of shells killed four people.