As Ukraine's pro-European protests descend into violence, with demonstrators sustaining their first fatalities, attention has focused on the far-right youth group many have blamed for radicalizing the protest movement.
Activists from Pravyy Sektor (Right Sector), a loose alliance of nationalist organizations, have been at the forefront of the bloody clashes that have pitted protesters against police since January 19. At least two demonstrators were shot dead on January 22.
Andrei Tarasenko, Pravyy Sektor's coordinator, warned of a full-blown civil war if police continued to use force against the protesters:
"If they attack and try to carry out a bloody crackdown, I think there will be a massacre," he told RFE/RL. "Guerilla warfare will begin in Ukraine."
Pravyy Sektor was formed in the early days of the protests, sparked by President Viktor Yanukovych's abrupt decision in late November to walk away from a landmark association deal with the EU.
Tarasenko says Pravyy Sektor's goal is to oust the current government and "build a nation state" in Ukraine.
The group has demanded that Yanukovych step down, saying it would give him and his family 24 hours to leave the country safely.
Unlike mainstream opposition leaders, it firmly rejects any negotiation with authorities.
Instead, it has used the VKontakte social-networking website to prepare its sympathizers for battle and call for donations of items such as slingshots, steel balls, gasoline, laser pointers, glass bottles, chains, and pyrotechnics.
"Authorities are using all possible methods against people, why shouldn't people be able to defend themselves with truncheons, too?" says Igor Mazor, a member of the group.
Many Ukrainians are watching with dismay as the initially peaceful rallies escalate into vicious street fighting.
After two months of fruitless protests, however, Tarasenko claims increasing numbers of Ukrainians are embracing Pravyy Sektor's radical methods.
"Yanukovych must resign," he says. "People are ready to do anything for this to happen. And I'm not talking just about Pravyy Sektor here. I'm talking about Ukraine."
Ukraine's three main opposition parties blamed Yanukovych and Interior Minister Vitali Zakharcheko for the deaths on January 22.
Prime Minister Mykola Azarov, in turn, pinned the blame on the hard core of radical protesters, branding them "terrorists" and "criminals."
Azarov also warned that authorities could act under controversial new laws that essentially ban mass protests in Ukraine.
But analysts warn that forcing Pravyy Sektor off the streets, far from easing tensions, could actually further escalate the violence.
"I've looked into these people's eyes and I've seen no fear," says political commentator Taras Berezovets. "Berkut [Ukrainian riot police] won't be able to simply disperse them."
RFE/RL's Russian Service correspondent Vladimir Ivakhnenko contributed to this report from Kyiv