ISTANBUL (AP) -- The leaders of Russia and Turkey on Monday downplayed differences over the Syrian civil war, saying they shared the common goal of trying to end the humanitarian crisis there and hailing their countries' booming trade ties.
President Vladimir Putin of Russia, one of Syria's few remaining allies, said he understood Turkish concerns about its border security after Syrian shells hit Turkish territory in recent months.
But he warned that Turkey's request that NATO deploy Patriot missiles on its border with Syria could escalate fears of a wider conflict. Turkey and its Western and Arab allies are calling for the ouster of Syrian President Bashar Assad.
"We share Turkey's concern about the developments on the border," said Putin. "But we are calling for restraint because increasing (military) potential will not settle the situation but create the opposite effect."
After meeting Putin in Istanbul, Turkish Prime Minister Recep Tayyip Erdogan said the Turkish and Russian foreign ministers will work together more intensively on the Syrian problem.
Russia has blocked tough action against Syria with its Security Council vote at the United Nations, while Turkey has urged the establishment of an internationally protected buffer zone for civilians in Syria.
Putin and Erdogan emphasized the blossoming economic ties between their two countries, saying they should aim for bilateral trade to triple to $100 billion a year. Russian and Turkish officials signed 10 agreements on trade, energy, finance, banking and other issues.
Putin, who was making his first trip after a two-month hiatus that raised concerns about his health, showed some rigidity in his movements but no sign of pain or difficulty.
He walked past television cameras and climbed the podium without showing discomfort, and seemed at ease turning around in his seat and shaking hands with officials during the signing ceremony.
His spokesman, Dmitry Peskov, shrugged off a question about whether the president felt any negative effects of air travel, saying Putin was fine.