Turkey and Russia agreed a ceasefire deal on Thursday in northwestern Syrias Idlib region, their two leaders said after lengthy talks in Moscow. Russian President Vladimir Putin, standing next to his Turkish counterpart Recep Tayyip Erdogan, said he hoped their agreement would lead to a halt of military action in Syrias last opposition stronghold in the far northwest of the country. "I express hope that these agreements will serve as a good basis for a cessation of military activity in the Idlib de-escalation zone (and) stop the suffering of the peaceful population and the growing humanitarian crisis," Putin said. Erdogan told reporters the truce would come into effect at midnight on Thursday. "We will work together to supply aid for the Syrians in need," he said, adding that Turkey retained the right "to respond to all (Syrian) regime attacks in the field." The Kremlin said the two leaders had spoken for three hours on their own before being joined by their officials. The two leaders also agreed to establish a secure corridor near the M4 highway, which runs east to west through Idlib, and hold joint patrols along the road from March 15. In a joint statement read out by the Turkish and Russian foreign ministers, the two sides said the corridor would stretch 6 km to the north and 6 km to the south of the M4 – effectively advancing Russias presence further north into Idlib. They said their defense ministers would agree on the parameters of the corridor within seven days. A Russia-backed Syrian offensive to regain control over Idlib — the last opposition-controlled region in the country — has resulted in Turkey sending thousands of troops into Idlib to repel the Syrian army. Clashes on the ground and in the air have left dozens dead on both sides.