A Russian-backed separatist leader in eastern Ukraine said on Monday that full-scale war could break out there at any time and his forces might need to turn to Moscow for support.
Denis Pushilin, head of the breakaway Donetsk People's Republic, said there was a high likelihood of a war that would bring huge casualties, although it would be "madness" to embrace such a conflict.
"First of all we rely on ourselves, but we do not rule out that we will be forced to turn to Russia if Ukraine, with the support of Western countries, passes a certain line," he told Reuters in an interview in his fortified office.
Some 15,000 people have been killed since 2014 in fighting between the Russian-backed separatists and the Ukrainian army, according to the government in Kyiv.
Tensions have risen sharply since November, when Russia started massing a force of more than 100,000 troops on Ukraine's borders, raising fears of a much bigger war despite Moscow's insistence it has no plan to invade.
Pushilin said the separatists had gaps in their weaponry when it came to electronic warfare, air defenses and the ability to counter the Ukrainian army's Turkish-made drones.
He said they were not in contact with Russia about providing weapons, but noted an "important statement" by a ruling party politician in the Russian parliament last month who said Moscow should supply certain types of arms to the separatists in Donetsk and neighboring Luhansk.
In a second Reuters interview, an influential commander in the breakaway region, Alexander Khodakovsky, urged Russia to send 30,000 soldiers to reinforce the separatists and operate new weapons systems he hoped Moscow would supply.
Russia says the Ukraine conflict is a civil war in which it has no involvement, but senior Ukrainian government sources say Russia has deployed a military force of about 2,000 to support an estimated 35,000 separatists in the eastern Donbass region.
"Russian forces have been waging war in Donbass for eight years," Ukrainian Foreign Ministry spokesman Oleg Nikolenko said.
Pushilin declined to give a clear answer when asked about the likelihood or desirability of Russia recognizing his breakaway territory as an independent state, as some deputies in the Russian parliament are urging President Vladimir Putin to do. He said it would be "selfish" to focus only on the separatist regions and ignore the interests of ethnic Russians in other parts of Ukraine.
Without providing evidence, he said there was a "constant threat of military actions" on the Ukrainian side, and clear signs of active preparations.
Ukraine has repeatedly denied Russian accusations that it is planning to take back the breakaway regions by force.
"I'm even talking about some kind of big war. Which I would like to avoid, because this war could be the last one for humanity," Pushilin said, accusing the West of exacerbating the situation.
He criticized "naive" statements by U.S. officials that the timing of any conflict would be influenced by whether the ground was frozen.
"It could all start at any moment, regardless of weather conditions. Sometimes unfavorable weather conditions are good cover for launching an attack."