The Brussels attacks have pushed security to the forefront of Britain's EU referendum campaign this week, as intelligence experts came out of the shadows to press the benefits and disadvantages of membership.
Dutch Prime Minister Mark Rutte defended an EU cooperation deal with Ukraine as vital for European stability only months before a referendum Dutch eurosceptics have forced on the accord.
British Prime Minister David Cameron is to promise an additional £12 billion to strengthen the defence forces when he unveils a five-year strategic review on Monday.
President Vladimir Putin pledged Russia would build weapons that could pierce any anti-missile shield as he accused the United States and its allies of looking to shackle Moscow's nuclear capabilities.
US Defense Secretary Ashton Carter said he expected more raids targeting the Islamic State group similar to the mission that freed dozens of captives but left an American commando dead in Iraq.
US President Barack Obama vetoed a $612 billion defense spending bill, saying it prevented the closure of Guantanamo Bay prison and wasted money on unwanted programs.
Australia will spend Aus$1.3 billion (US$1 billion) on next-generation armoured land vehicles for its army, Prime Minister Malcolm Turnbull said as he announced the latest update to modernise the nation's military.
Japan's parliament passed contentious security bills into law early Saturday, in a move that could see Japanese troops fight abroad for the first time in 70 years.