Turkey and Russia have agreed on steps to "normalise" the situation in northwest Syria, President Vladimir Putin said on Tuesday after a meeting with Recep Tayyip Erdogan.
The two countries back different sides in war-torn Syria with Moscow backing Syrian President Bashar al-Assad while Ankara supports rebels.
However, they signed the Sochi Memorandum last year, pledging to create a demilitarised zoned in Syria's Idlib governate.
The northwestern province, which borders Turkey, is the last rebel stronghold in Syria.
But less than two weeks ago, a Turkish convoy loaded with munitions and which had crossed into Idlib province was targeted by Syrian airstrikes. Syrian state media said the convoy was meant to help insurgents and blasted Turkey's "aggressive" move. It affirmed "the determination of the Syrian Arab Army to keep hunting the remnants of terrorists".
Talking to reporters at the end of Erdogan's one-day trip to Russia, the two leaders underlined that Syria should remain a unified country.
Erdogan added, however, that Turkey had the right to self-defence on its border.
"I conveyed our country's determination on this matter personally to my dear friend Mr Putin," he said.
The Turkish leader added that Ankara would continue its defence industry cooperation with Moscow.
Last month, Turkey received the first shipment of a Russian-made missile defence system, a move that has fanned tensions with its NATO allies and saw it removed from a joint F-35 strike fighter programme.
The US argued that the Russian S-400 system could be used to gather data on the capabilities of the F-35 fighter jet and that the information could end up in Russian hands.
Earlier in the day, Erdogan and Putin visited Russia's 14th International Aviation an Space Salon where they watched demonstration flights of Russian combat aircraft including the Su-34, Su-35 and SU-57.
Putin said he and Erdogan discussed cooperation on Russia's Su-35 jet and possible joint work on its new Su-57.