The OSCE Special Monitoring Mission to Ukraine (OSCE SMM) has reported numerous violations of the Minsk agreements in the Donetsk airport area and near Mariupol in its spot report as of 7:30 p.m. on June 21.

"During the weekend, fighting intensified in Donetsk, where substantially increased shelling was observed. A high level of violence was observed in and around Donetsk airport," said the report released on Monday evening.

"Over a period of two days, from its position at the Joint Centre for Control and Co-ordination (JCCC) observation point at Donetsk central railway station ("DPR"-controlled, 8km north-west of Donetsk city centre) and other observation posts in and near Donetsk city centre, the SMM observed more than 500 incoming and outgoing explosions consistent with artillery and mortar fire," it said.

"The SMM heard 187 of these explosions from its observation post at the central railway station, at locations to the north, north-north-west, south-west, and north-east at distances 2 to 8km," the monitors reported.

An increase in ceasefire violations was also observed in areas near Mariupol over the weekend. In government-controlled areas 14-30km north-east of Mariupol, the SMM heard over 170 explosions, mostly incoming and outgoing, consistent with tank (around 100 rounds) and artillery fire.

In Luhansk the situation was calm over the weekend with sporadic shelling observed.

The OSCE monitors reported having observed heavy armaments of the Ukrainian army and the DPR militia in locations prohibited by the Minsk agreements.