"Estonia's defense attaché is hereby invited from Sept. 19-21 to participate in a briefing, observation of the exercise and a visit to a Belrusian defense industry company," it said on the Ministry of Defence's webite. "The invitation does not clarify the details of the events."

The Belarusian Ministry of Defence's inviation to Estonia was dated July 21.

"Even thouugh this does not concern the monitoring of the exercise within the framework of the OSCE, the invitation is a welcome step on Belarus' part in making the exercise tranparent," the Estonian ministry commented. "The Ministry of Defence is prepared to participate in the events organized by Belarus on the basis of bilateral relations."

According to the ministry, Russia has not notified OSCE officially or on a voluntary basis of Zapad 2017.

"Previously, it has been identified that Russia has split military exercises, not reported them or reported them as smaller than they actually were," noted the Estonian ministry.