Ukraine says six of its soldiers were killed during an ambush by militants on Tuesday.

CNN reports the Ukrainian Defense Ministry called it a "terrorist attack." The network adds:

"The incident took place in the village of Oktyabrski in the Slovyansk region, about 20 kilometers from Kramatorsk, during 'a unit movement from the military base.' The location is in volatile eastern Ukraine." 'Our soldiers were attacked in an ambush. Terrorists attacked our land troops with grenades. The attackers were more than 30 people and set an ambush near the river,' the ministry said." 'After a long shootout, six soldiers of The Ukrainian Armed Services were killed,' the statement said."In another incident in eastern Ukraine, a separatist leader has been injured in a suspected assassination attempt, a spokesman said Tuesday, amid continuing turmoil in the wake of a controversial weekend referendum on independence."

On the diplomatic front, Germany's foreign minister was trying to jumpstart talks between the central government in Kiev and pro-Russian militants in the east.

The AP reports that Frank-Walter Steinmeier was trying to implement a plan outlined by the Organization for Security and Cooperation in Europe, which calls for an end to the violence that erupted when militants took over buildings in the east, and Ukraine launched military operations to retake them.

The AP adds:

"Russia called Tuesday for a swift implementation of the OSCE plan, saying its demand to end violence means that the central government in Kiev should stop its military operation to recapture buildings in the east, lift its blockade of cities and towns, pull its forces from eastern regions and release all political prisoners." 'We are demanding [they] stop intimidating civilians by using force or threatening to use it,' Russia's Foreign Ministry said in a statement."It added that it expects separatists in Ukraine's Donetsk and Luhansk regions to respond in kind if Kiev does all that."Copyright 2016 NPR. To see more, visit