Turkish President Recep Tayyip Erdogan urged the EU consider a no-fly zone and safe haven area in Syria during talks to address Europe's spiralling migrant crisis.
US Defence Secretary Ashton Carter arrived in Madrid, beginning a European tour amid alarm over Russian bombardments in Syria and the refugee crisis sparked by the conflict.
British Prime Minister David Cameron urged Russian President Vladimir Putin to "change direction" in Syria and recognise that its President Bashar al-Assad must be replaced.
Chechen strongman Ramzan Kadyrov called on the Kremlin to let a contingent from his region fight the Islamic State in Syria, where Russia launched air strikes earlier this week.
The Syrian crisis can only be solved through peaceful ways, Kazakhstan’s Foreign Affairs Minister Yerlan Idrissov said at the General Policy Debates at the UN headquarters in New York.
Russian air strikes in Syria will last for three to four months and will intensify, a senior Russian lawmaker said as President Vladimir Putin was due in Paris for talks.
Turkey's prime minister used his UN General Assembly speech to press demands for a "safe zone" to be created in Syria to protect civilians fleeing barrel bombs and the Islamic State group.
Russia rejected accusations that Moscow had bombed moderate rebel factions fighting President Bashar al-Assad instead of Islamic State fighters and had hit civilians.
NATO General Philip Breedlove expressed concern Monday about the strength of Russia's military build-up in northwestern Syria and the apparent creation of a defensive "bubble" in the Mediterranean.
France gave cautious backing at the United Nations to a call from Russian President Vladimir Putin for a "broad coalition" to fight the Islamic State group in Syria.
British Prime Minister David Cameron called for discussions on how to bring about political transition in Syria as he prepares to meet world leaders at the United Nations General Assembly.
Iranian President Hassan Rouhani said in an interview that he is ready to discuss a "plan of action" for Syria's post-war future after the Islamic State group is defeated.
Russia has shocked the West by boosting its military presence in Syria as President Vladimir Putin seeks to not just defeat Islamic State radicals but also to gain a firm foothold in the strategic Middle Eastern country.
The United States and Russia could find ways to cooperate on the crisis in Syria, Pentagon chief Ashton Carter said, as Moscow continues a military build-up in the war-torn nation.