LONDON - US Secretary of State John Kerry has launched a new round of intense diplomatic talks with Russia as the crisis in Ukraine deepened, with ethnic Russian protesters in three cities holding on to government buildings they occupied earlier in the week to push demands for a regional referendum on independence.
However, officials in most European capitals are gloomy about the chances of any diplomatic breakthrough, for they fear that Ukraine may be about to enter a prolonged and intractable internal crisis.
The pro-Russian protests in Donetsk, Kharkiv and Luhansk - three dusty, Soviet-era industrial cities in eastern Ukraine where ethnic Russians make up much of the population - are not very large, with at most a few hundred people in each case.
Nor is it obvious that the demonstrators are representative of the prevailing opinion in their cities. In an extensive regional opinion poll conducted recently by the International Republican Institute, a US think-tank funded by the American government, 45 per cent of the local respondents expressed a desire to remain within a unified Ukraine and only 5 per cent wanted to become part of Russia. The rest opted for a variety of autonomy schemes.
Yet having confined themselves over the past few weeks to defiant displays of Russian flags, the demonstrators are now much more violent, and their demands more extreme: self-appointed "deputies" have gone as far as proclaiming the "People's Republic of Donetsk" in the hometown of former Ukrainian president Viktor Yanukovych, who was ousted in late February.
The Ukrainian government's claim that many of the rioters are not local and may have been bussed in from as far as Russia for the purpose remains unverifiable, although a comical incident earlier this week - when demonstrators stormed the city opera house in Kharkiv in the mistaken belief that the grand building must be a government installation - does suggest that at least some of the men of violence were unfamiliar with the layout of the cities in which they were protesting.
Yet there is little doubt about Russia's stance: Moscow's state-controlled TV is lavishing attention on the demonstrations, while Russian Foreign Minister Sergei Lavrov claims that the events "indicate the need to respect the aspirations of the residents of southeastern Ukraine… to protect their language, culture and socioeconomic rights".
Although Russia has frequently threatened to use force to protect ethnic Russians in Ukraine and Russian troops continue to be massed within striking distance of all the rioting cities, the assumption among Western security analysts is that the prospect of a further Russian military incursion similar to that undertaken last month in Crimea remains small.
Further confirmation of this view came from Mr Viktor Ozerov, head of the defence and security committee of Russia's Upper House of Parliament, who said yesterday that Russia cannot send "peacekeepers" into Donetsk as the protesters demanded.