The Red Cross is to lead an international humanitarian aid operation into Ukraine's conflict-stricken province of Luhansk with assistance from Russia, the European Union and the US, Kiev has said.
Ukrainian officials took pains to specify that the government was behind the humanitarian convoy initiative, and that Moscow was only one of several countries involved. They also said the mission had the backing of US President Barack Obama.
Monday's announcement came hours after Moscow said it was dispatching a humanitarian convoy into eastern Ukraine, where pro-Russia separatists are battling the central government in Kiev.
"Apart from deliveries provided by Ukraine, the mission will feature an international component, including aid provided to the International Committee of the Red Cross by the United States, the EU, as well as Russia," Ukraine's Foreign Ministry said in a statement.
The ministry also laid out specific conditions for the convoy to ensure only civilians in need benefit.
"Humanitarian aid will only be distributed among the civilian population of the Luhansk province, which has long been suffering from the actions of illegal armed gangs," the ministry said.
Ukraine and the West, who had feared Russia could use humanitarian mission as a pretext for sending troops into rebel-held territory, have previously opposed such initiatives.
Ukraine and its allies have long accused Moscow of arming and supporting the rebels, a charge that Russia has denied.
Earlier, European Commission chief Jose Manuel Barroso said he had warned Russian President Vladimir Putin in a telephone call "against any unilateral military actions in Ukraine, under any pretext, including humanitarian," the AP news agency reported.
'Spanner in the works'
Russian Foreign Minister Sergey Lavrov said Russia had agreed on details of a humanitarian mission with the Ukrainian leadership.
"I hope that our Western partners will not put a spanner in the works," he said.
The Interfax-Ukraine news agency quoted Ukrainian Foreign Ministry spokesman Yevhen Perebiynis as saying the humanitarian convoy could only be carried out under specific conditions.
He said all aid would have to cross into Ukraine through border crossings under Kiev's control.
At least 100km of the long Russian-Ukrainian border is currently in rebel hands.
In the last week, Ukrainian government forces have been closing in on the few remaining pro-Russian rebel strongholds in eastern Ukraine, including Donetsk, the largest city in rebel hands. Hundreds of thousands have been fleeing the fighting.
Some of the heaviest impact of the fighting on civilians has been seen in Luhansk, the rebel-held capital of the Luhansk province that had a pre-war population of 420,000.
City authorities said on Monday that the 250,000 residents remaining have had no electricity or water supplies for nine days.
Food, medicine and fuel are also not being delivered, the Luhansk city government said.
Late Monday, the International Committee of the Red Cross (ICRC) said they are extremely concerned about the plight of people in eastern Ukraine.
"It is urgent that aid reaches people in Lugansk and in other areas in the eastern part of the country, which have sustained heavy fighting over the past weeks," said Laurent Corbaz, the ICRC's head of operations for Europe and Central Asia.
"The situation is critical – thousands of people are reported to be without access to water, electricity and medical aid." Corbaz said.
Also on Monday, rockets slammed into a high-security prison in the main rebel-held city of Donetsk, igniting a riot that allowed more than 100 prisoners to flee, authorities said.
Donetsk city council spokesman Maxim Rovinsky said a direct rocket hit had killed at least one inmate and left three others severely wounded. In the chaos, he said 106 prisoners escaped, included some jailed for murder, robbery and rape, AP reported.
Many of those in Russian-speaking eastern Ukraine distrust the new central government in Kiev, which came to power after the February ousting of former President Viktor Yanukovych, whose power base was mainly in eastern Ukraine.
Fighting began a month after Russia annexed Ukraine's peninsula of Crimea in March.