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.
British leader David Cameron got "distracted" and French President Nicolas Sarkozy wanted to promote his country during the 2011 military intervention in Libya, US President Barack Obama said.
Official moves towards the deployment -- fiercely opposed by China -- of a US missile defence system in South Korea highlight the inherent dangers of disunity in dealing with North Korea's growing military threat.
North Korea said it had successfully tested a miniature hydrogen bomb. If confirmed, this would place it among a small group of countries with such dangerous weapons.
Wars are no longer the same they used to be. Now they are hybrids of economic, political, informational, internal and other wars, and the army has to adjust to the new specifics: Nursultan Nazarbayev.
President Recep Tayyip Erdogan sought to play down tensions with Russia after Turkey's downing of a Russian warplane on the Syria border sparked fears among NATO allies of a wider conflict.
NATO chief Jens Stoltenberg said that the military alliance stands by key ally Turkey after it shot down a Russia fighter jet on the Syrian border but urged both sides to try to calm the crisis.
European Union president Donald Tusk called for calm after Turkey, a candidate for membership of the bloc, shot down a Russian war plane on the Syrian border.
UN envoy Martin Kobler urged rival Libyan politicians to sign up to a UN-brokered agreement for power sharing in the war-torn nation during weekend talks with both sides.
Hillary Clinton called for a US-led global fight to defeat the Islamic State group and shut down its flow of fighters, propaganda and weapons in the wake of the Paris attacks.
President Vladimir Putin ordered the Russian navy in the Mediterranean to establish contact with its French counterparts and work together "as allies" in a campaign against the Islamic State group in Syria.