This is reported by the OSCE Headquarters.
"At around 19:15 on December 18, while at its forward patrol base on the northern edge of government-controlled Popasna (69km west of Luhansk), the SMM heard five undetermined explosions 500-600m north-east, followed by three explosions assessed as outgoing rounds of undetermined weapons within 1.5km south-west," the statement said.
The SMM staff (consisting of five monitoring officers, a paramedic and a language assistant) at the forward patrol base immediately gathered near the base’s basement shelter and remained there the entire evening. At around 19:50, the SMM informed via telephone Ukrainian Armed Forces and Russian Federation Armed Forces officers of the Joint Centre for Control and Co-ordination (JCCC) of the shelling; the latter told the Mission to contact the armed formations directly.
At around 10:00 on December 19, the SMM left the forward patrol base and subsequently reached government-controlled Sievierodonetsk (74km north-west of Luhansk) safely.