April 15 (UPI) -- Military forces of Turkey and Russia on Wednesday made their fourth joint ground patrol in the past month in Syria's heavily contested northwest to monitor a cease-fire, officials said.
The Russian Reconciliation Center for Syria, part of Moscow's military, also said the troops conducted the patrol.
"Fourth joint Turkish-Russian land patrol was conducted today [Wednesday] by air and ground vehicles on M4 motorway in Syria's Idlib province, as part of the earlier TR-RF agreement," the Turkish Defense Ministry tweeted.
Turkish and Russian forces made the patrol along the M4 highway, located about 20 miles from the Turkey-Syria border, which runs between Aleppo and Al Hasakah. It's considered a strategic corridor in Idlib province, the last stronghold of rebels opposing the regime of Syrian President Bashar al-Assad.
The joint patrols are a key element of the March 6 cease-fire under which Turkey, which has long supported insurgent forces, and Moscow agreed to halt escalating violence in Idlib.
Many months of fighting in Idlib province has displaced hundreds of thousands there and sent them to seek shelter across the border in Turkey.
The joint Russian-Turkish patrols along the M4 highway started on March 15.