The OSCE Special Monitoring Mission (SMM) to Ukraine has reported an undetermined explosion occurred 300-500 meters from its patrols in Luhansk region.
"At 11:04 on May 20, two SMM patrols consisting of ten members and four armored vehicles positioned themselves about 20m south of a checkpoint of the armed formations inside the disengagement area near Zolote (government-controlled, 60km west of Luhansk) on its southern edge. All patrol members were outside the vehicles, five of whom were speaking with two unarmed members of the armed formations, and saw an additional five to eight members of the armed formations (one armed with an assault rifle (AK-type), the remainder unarmed) walking around the checkpoint inside the disengagement area. At 11:06, the patrol members heard an undetermined explosion 300-500m north (assessed as inside the disengagement area)," the OSCE SMM said in a spot report on May 20, 2018.
The SMM said its monitors had previously observed an anti-aircraft gun (ZU-23, 23mm) about 10m north-west of the abovementioned checkpoint inside the disengagement area.
"Both patrols immediately left the area and returned safely to their bases in Sievierodonetsk (government-controlled, 74km north-west of Luhansk) and Kadiivka (formerly Stakhanov, non-government-controlled, 50km west of Luhansk), respectively," the monitors said.