Turkey on Monday sent back to Russia the corpse of a pilot killed when his plane was shot down by the Turkish air force for allegedly violating its air space on the Syrian border.
The European Union and Turkey agreed on a deal to stem the migrant crisis, including a three-billion-euro ($3.2-billion) aid package for Syrian refugees in Turkey.
Moscow slapped sanctions on Ankara as the war of words over a downed Russian warplane escalated, with Turkish strongman Recep Tayyip Erdogan warning Russia not to "play with fire".
Secretary of State John Kerry spoke by phone with Russia's foreign minister and urged a de-escalation of tensions after Turkey shot down a Russian warplane near the Turkey-Syria border.
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.
Russian Foreign Minister Sergei Lavrov recommended against Russians travelling to Turkey and cancelled his own planned visit after Ankara shot down a Russian fighter jet.
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.
Greek Prime Minister Alexi Tsipras held talks with the Greek orthodox patriarch as he embarked on his first official visit to Turkey set to be devoted to grappling with the huge flow of refugees entering his country from Turkish territory.