"The mission registered numerous groups of young people in military-style clothing crossing the border in both directions during the week. The observers also spotted ambulances evacuating the wounded supporters of the DPR several times," the statement says.
In addition, the cases of the armed Mi-24 helicopters flying over the border crossing point became more frequent over the last three days.
"The helicopters flew very close to the border crossing point at night. The observers claimed that the helicopters did not violate the airspace of Ukraine in the area visible from the checkpoint during the daytime," the report states.
The artillery explosions were heard on August 10 and 12. According to the information of the OSCE the fire of heavy guns was carried out twice in the northwestern direction.
"The sound was similar to the one produced by a multiple launch rocket system in both cases," the observers said.
Head of the OSCE mission in the Rostov region Paul Picard said of the Commission for checkpoints Gukovo and Donetsk on the Russian-Ukrainian border operation start on July 30.