The new Western-backed Ukrainian president has released a peace plan designed to end a separatist uprising in the east. Russia, meanwhile, has rejected criticism of a troop deployment to its shared border with Ukraine.
The 14-point peace plan, unveiled by Ukrainian President Petro Poroshenko on Friday, follows months of conflict from a pro-Russian separatist uprising in eastern Ukraine, which began in April.
The plan demands the disarmament of rebels in the east, in return for the decentralization of power in Ukraine through constitutional reform.
It drops criminal charges against fighters who committed no "serious crimes," and provides "a guaranteed corridor for Russian and Ukrainian mercenaries to leave" the conflict zone.
Poroshenko also calls for the creation of a 10-kilometer (6.25 mile) demilitarized zone on the border with Russia, to reduce the flow of gunmen and military equipment that both Ukraine and the United States say have been flooding in from Russia in recent weeks.
Ukraine and Russia share a 1900-kilometer (1190 mile) border, and tightening control of it is becoming a major challenge for the government in Kyiv. Poroshenko has argued that long-lasting peace can only be accomplished when the border with Russia is fully sealed - a victory claimed by Ukraine's parliament speaker on Friday but one quickly denied by rebel leaders.
Installed on June 7, Poroshenko is under pressure to end rebellions in Ukraine's Russian-speaking east, by securing both support from Moscow as well as his backers in the West.
It is not yet clear if the whole of his proposed buffer zone would be on Ukraine's side of the border, or part of it on the Russian side, nor the status people living in border areas.
Poroshenko has also called on "local government bodies to resume their operations" - a demand rejected by separatist leaders, who have declared independence from Kyiv and taken control of administration buildings in about a dozen cities and towns in Ukraine's east.
Pro-Russian separatists earlier this week rejected any strategy for bringing about a ceasefire.
The crisis in Ukraine began last year amid mass protests against former president Viktor Yanokovych, who abandoned a key EU agreement in favor with closer ties with Moscow. After his overthrow in February, Russia annexed the Crimea region in March, and the uprising in Ukraine's east began in April.
The unveiling of the peace plan on Friday comes despite a second day of heavy fighting in the east, in which government troops claimed to have killed 300 rebels.
Russia sends troops to border
The Kremlin on Friday announced it had sent armed forces near Ukraine, with a spokesperson for President Vladimir Putin saying the move had been planned for several weeks.
"In this case we cannot speak of any concentration of troops other than measures to reinforce the protection of Russia's borders, which are being carried out on President Vladimir Putin's direct orders," spokesman Dmitry Peskov said.
Peskov said the deployment had been discussed with Western partners and criticizm of it was therefore "surprising."
On Thursday, NATO chief Anders Fogh Rasmussen labeled Russia's move to send a few thousand more troops to the border as a "very regrettable step backwards."
That same day, German Chancellor Angela Merkel and French President Francois Hollande telephoned Putin, calling on him to convince pro-Russian separatists in Ukraine's east to lay down their arms.
jr/kms (Reuters, dpa, AFP)
Germany's U19s have won the European Championship in Hungary, but after the seniors' 2014 World Cup win, this youth level triumph is far from surprising. Could it mark a sustained cycle of German success?
The German athletics federation has excluded the Paralympic champion Markus Rehm from its team for the upcoming European Championships. Rehm says he may contest the decision.