Ukrainian government troops have taken control of "significant parts" of one of two remaining separatist-held cities in eastern Ukraine and seized a strategic railway hub needed to resupply the second, a national security spokesman announced in Kiev on Wednesday.
The advances reported by Col. Andriy Lysenko of the Ukrainian National Security and Defense Council came at a heavy toll for both sides as nine Ukrainian soldiers died in the fighting and Russian media quoted insurgent leaders as saying 34 civilians were killed.
Fighting has intensified since the July 17 downing of a Malaysian passenger jet over territory held by pro-Russia separatists. Western intelligence and the Ukrainian government blame the separatists for the plane's destruction and Russian President Vladimir Putin for supplying the missile and its launch system, accusations the Kremlin has denied.
Fierce fighting in and around Luhansk and Donetsk in recent days has pushed the separatists out of key suburbs and cut supply lines to the nearly 5-month-old rebellion against the government in Kiev.
Running gun battles in the streets and artillery exchanges have also prevented delivery of Russian aid to civilians trapped in the cities as neutral escorts from the International Committee for the Red Cross have not received reliable guarantees from the combatants for safe passage.
On Wednesday, the Red Cross official in charge of European and Central Asian operations, Laurent Corbaz, arrived in Moscow and met with Deputy Foreign Minister Sergei Ryabkov in an effort to obtain security assurances needed for the agency's workers to escort Russia's 280-vehicle convoy into Luhansk.
Ukrainian President Petro Poroshenko initially resisted Putin's push to send relief supplies to the Russian-speaking areas of eastern Ukraine that have been the scenes of violent clashes since late March, expressing concerns that the cargo could include military supplies for the beleaguered separatists.
Poroshenko relented after Russian authorities agreed to his conditions that the convoy enter Ukraine through a government-controlled border crossing and be inspected by Kiev customs authorities and transferred to Red Cross vehicles for onward delivery to the insurgent-held areas. However, the convoy diverted to Kamensk-Shakhtinsky in Russia's Rostov region, about 20 miles from a separatist-controlled crossing east of Luhansk, where it remains pending resolution of the standoff over permission to enter Ukraine.
A Russian Foreign Ministry statement said an advance party from the 40-plus Red Cross officials in the Rostov area had set out Wednesday to inspect a proposed route to Luhansk for the convoy.
Luhansk, a city of 465,000 before separatists seized its regional government offices in late March, has seen more than half its population flee, mostly in the last month as government troops have closed in on the militants.
The rebellion has also been weakened by the departure of Russian citizens, including special forces veterans, from the purported governments and militias of the self-proclaimed People's Republics of Donetsk and Luhansk. The separatist movement is now in the hands of local pro-Russia militants with less experience in urban combat than the recently departed Russian mercenaries.
The Ukrainian counter-offensive to recover the separatists' last redoubts on Wednesday captured a key railway hub in the town of Ilovaysk, about 30 miles east of Donetsk, Lysenko said. Russia's Itar-Tass news agency said fighting around Donetsk had resulted in the deaths of 34 civilians over the previous 24 hours.
While the fighting continued unabated, Poroshenko and Putin announced on Tuesday that they would attend a gathering of the Kremlin-controlled Eurasian Customs Union next week to discuss the conflict and the two nations' trade relations, which have been altered by Ukraine's signing of an association agreement with the 28-nation European Union.
That alliance, initially set to be formalized nine months ago, was the catalyst for a Ukrainian rebellion against former President Viktor Yanukovich, a pliable Kremlin ally deposed in a February revolt. Putin then sent troops to Ukraine's Crimea peninsula to secure Russia's military installations there, inspiring the pro-Russia separatists in eastern Ukraine to seize other territory in hopes of having it annexed to Russia.
Special correspondent Gorst reported from Moscow and staff writer Williams from Los Angeles.