President Vladimir Putin's spokesman said Friday Ukraine's offensive against pro-Russian rebels in the east dealt a final blow to a peace deal on the crisis, adding a Moscow envoy had been dispatched there to help negotiate the release of kidnapped OSCE monitors.
"While Russia is making efforts to de-escalate and settle the conflict, the Kiev regime moved combat air forces against peaceful settlements, began a reprisal raid, essentially finishing off the last hope for the feasibility of the Geneva accords," Dmitry Peskov was quoted as saying by Russian news agencies.
Peskov also said the Russian president had sent special envoy Vladimir Lukin to east Ukraine to help negotiate the release of the team of observers from the Organization for Security and Cooperation in Europe, who were detained by rebels while trying to monitor the faltering Geneva peace deal.
He said Moscow was "extremely worried" that Lukin as well as journalists from Russia and other countries were now working in a conflict zone.
"Of course, we demand that measures be taken to ensure their safety," Peskov said.
Russian officials and television news anchors described the offensive in the east of Ukraine as a "reprisal raid", after Putin first used the term to describe Kiev's military operation against the rebels in late April.
The term "reprisal raid" is widely used in Russian history books to describe military operations by Nazi troops against civilians during World War II.
Separately, Russia urged the OSCE to help stop Ukraine's military offensive in the eastern city of Slavyansk.
"We have gotten in touch with the OSCE leadership over the offensive of the armed forces (of Ukraine) and demanded that they take steps to stop this reprisal raid," Andrei Kelin, Russia's envoy to the pan-European body, told the ITAR TASS news agency.
Kelin said Moscow had submitted its demands to OSCE Secretary General Lamberto Zannier and Swiss Foreign Minister Didier Burkhalter, the body's chairperson-in-office.
Kelin said Zannier had described what was happening in Slavyansk as "something terrible" that "has to be immediately stopped".
"Burkhalter is trying to get in touch with Ukraine's acting president Oleksandr Turchynov and Ukrainian Prime Minister Arseniy Yatsenyuk and the general secretary with Ukraine's acting foreign minister Andriy Deshchytsya," Kelin said.
"The Ukrainians are beginning to respond to them."
He said the situation of the military observers captured by the pro-Moscow rebels in the east had become "more complicated" and that they had been transferred to a "safe place".