The young men were trying their best to look tough and menacing in their combat gear, not all of them successfully. Their anger over the killing of hard-right leader Sashko Bily, however, seemed genuine enough. He would be avenged, they vowed; the “Russian agents” in the Ukrainian government would be hunted down and brought to justice.

Another patriotic campaign was being waged, in another part of Kiev, this time by young women, with the slogan of “Don’t Give It To A Russian”. The ‘It’ in this context was sex, which should not take place, as a sign of protest, with partners as well as in any new encounters with anyone of Russian stock, it exhorts.

These were two sets of the reactions to the drift and uncertainty in Kiev a little over a month after President Viktor Yanukovych was overthrown, when a brave new dawn was supposed to have come, and when the newly freed opposition leader Yulia Tymoshenko – who announced her candidacy for the presidency on Thursday – spoke to a crowd of thousands in Kiev. Now there is a sense of humiliation over the loss of Crimea; resentment about the old order retrenching themselves; and deep divisions within the opposition, with the killing of Oleksandr Muzychko, aka Sashko Bily, of the Right Sector, seen as a lethal example of this.

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The killing of Muzychko by the security forces after he fired first, according to the government, or a cold-blooded execution in the version being put out by his supporters, has raised fears of violent strife.

The ultra-nationalist group’s leader, Dmitry Yarosh, a candidate in the forthcoming presidential election, has demanded the resignation of the interior minister and arrest of members of the Sokol, or falcon, unit which had carried out the shooting. Roman Koval, an associate of Sashko Bily, in the Rivne region in the west of the country, was blunt about who should pay the price: “We will avenge ourselves on Arsen Avakov for the death of our brother. The shooting of Sashko Bily is a contract killing ordered by the minister.”

Shape Created with Sketch. Protests sparked by death of Sashko Bily Show all 10 left Created with Sketch. right Created with Sketch. Shape Created with Sketch. Protests sparked by death of Sashko Bily 1/10 Ukraine crisis Right Sector movement activists gather outside the parliament building to demand the immediate resignation of Internal Affairs Minister Arsen Avakov, in Kiev Reuters 2/10 Ukraine crisis A prominent Ukrainian far-right activist, part of a hard-line nationalist movement that played a leading role in the overthrow of President Viktor Yanukovich, was shot dead by police overnight, leading to protests Reuters 3/10 Ukraine crisis Activists of the Right Sector movement and their supporters gather outside the parliament building to demand the immediate resignation of Internal Affairs Minister Arsen Avakov Reuters 4/10 Ukraine crisis Members of the right wing ultra nationalist Right Sector group block the parliament building in Kiev, Ukraine AP 5/10 Ukraine crisis Members and supporters of the 'Right sector' political party attend a rally near the Ukrainian Parliament building in Kiev, Ukraine EPA 6/10 Ukraine crisis Members of the right wing ultra nationalist Right Sector group block the parliament building in Kiev AP 7/10 Ukraine crisis Ukrainian lawmaker Petro Poroshenko speaks with members and supporters of the 'Right sector' political party during their rally near the Ukrainian Parliament building in Kiev, Ukraine EPA 8/10 Ukraine crisis Protesters demand the Interior minister Arsen Avakov resignation in connection with the Sashko Bily killing EPA 9/10 Ukraine crisis Members and supporters of the 'Right sector' political party attend a rally near the Ukrainian Parliament building in Kiev, Ukraine EPA 10/10 Ukraine crisis Members and supporters of the 'Right sector' political party attend a rally near the Ukrainian Parliament building in Kiev, Ukraine EPA 1/10 Ukraine crisis Right Sector movement activists gather outside the parliament building to demand the immediate resignation of Internal Affairs Minister Arsen Avakov, in Kiev Reuters 2/10 Ukraine crisis A prominent Ukrainian far-right activist, part of a hard-line nationalist movement that played a leading role in the overthrow of President Viktor Yanukovich, was shot dead by police overnight, leading to protests Reuters 3/10 Ukraine crisis Activists of the Right Sector movement and their supporters gather outside the parliament building to demand the immediate resignation of Internal Affairs Minister Arsen Avakov Reuters 4/10 Ukraine crisis Members of the right wing ultra nationalist Right Sector group block the parliament building in Kiev, Ukraine AP 5/10 Ukraine crisis Members and supporters of the 'Right sector' political party attend a rally near the Ukrainian Parliament building in Kiev, Ukraine EPA 6/10 Ukraine crisis Members of the right wing ultra nationalist Right Sector group block the parliament building in Kiev AP 7/10 Ukraine crisis Ukrainian lawmaker Petro Poroshenko speaks with members and supporters of the 'Right sector' political party during their rally near the Ukrainian Parliament building in Kiev, Ukraine EPA 8/10 Ukraine crisis Protesters demand the Interior minister Arsen Avakov resignation in connection with the Sashko Bily killing EPA 9/10 Ukraine crisis Members and supporters of the 'Right sector' political party attend a rally near the Ukrainian Parliament building in Kiev, Ukraine EPA 10/10 Ukraine crisis Members and supporters of the 'Right sector' political party attend a rally near the Ukrainian Parliament building in Kiev, Ukraine EPA

The Ukrainian government condemned the “inflammatory statements” of the Right Sector while promising that an inquiry would be set up into the death. But for its cadres being taught unarmed combat in a suburban hall, this would be just a whitewash. Such was the distrust of those in power that these young men have reversed their decision not to join the National Guard being raised to augment the country’s small and ill-prepared army.

“We shall continue being a self-defence force; we are very disturbed by the killing; there are people in this government who are trying to target us,” said Nicolai Hordiyenko, 26, who said he had been in the thick of February’s fighting in the Maidan, the centre of protests in Kiev.

“We shall track down who is behind it; for sure the Russians have left people in their pay inside the ministries. Of course, we understand the need to form the National Guard, but we will do that after the election if there is a clean government.” Another member, security guard Ihor Minayaliuk, 36, was convinced of war with Moscow. “We shall keep training ... we are going to protect our country, our culture, our traditions; Ukrainians can get hold of weapons if necessary, believe me.”

The women’s “non-sex” campaign, however, was staying loyal to the Ukrainian military. In photos, activists backing the campaign appear in black and white T-shirts with folded palms, in prayer, according to some supporters, or a symbolic representation of a vagina, according to others. These T-shirts are on sale for 250 hryvina (about £14) each, with the proceeds going to the Defence Ministry.

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Katerina Venzhik, an editor of the news website Delo, and an organiser of the Facebook campaign, insisted: “It is going very well. This initiative was founded by a group of media and social activists who think that people around the world do not fully understand what Russians soldiers are really doing in Crimea. We also definitely wanted to make it clear that Ukrainian women prefer Ukrainian men!”

The campaign calls for supporters to “fight the enemy by whatever means”. It draws on history and culture, quoting the 1838 poem “Kateryna”, by Taras Shevchenko, polymath, nationalist and founder of Ukrainian literature: “Fall in love, o dark-browed maidens, but not with the Moskaly [Russians].” There are also references to Aristophanes’ comedy Lysistrata, where the eponymous heroine persuades the women of Greece to ban their husbands from the marital bed to force them to end the Peloponnesian War.

“Don’t Give It To A Russian” extends its plea across the border: “Russian women, would you like to join us? Our men are still at home, but yours are already at war.” Some supposedly offered to join, but there was also an outpouring of venom: the nationalist online magazine, “Sputnik & Pogrom”, insisted the women were nothing but prostitutes.

“Of course anyone with a brain cell can see that is a stupid contradiction, but these are very stupid people, stupid people who think they can just conquer another country,” said 26-year-old Oksana. “We are raising awareness, are making a stand, and sometimes this means making sacrifices.”

She is of Ukrainian extraction; her partner, and the parents of her partner, Leonid, 36, are from Russia. The couple have been together for 11 months and work in the same bank branch. “I am not in Crimea and I do not approve of what happened there, I do not see the logic behind all this,” Leonid said. “I also don’t think women have all the answers. Look who’s announced she is standing [for the presidency] today, she stole even more than Yanukovych.”

Yulia Tymoshenko’s declaration of candidature was expected. She told her campaign-launch press conference that no one was better qualified to tackle corruption in Ukraine, or to stand up to the Russians.

Ms Tymoshenko was imprisoned in 2011 after being found guilty of corruption over a gas deal she brokered with the Russians. She and her supporters strongly deny the charge, maintaining that it had been instigated by her bitter political rival, Mr Yanukovych. Vitali Klitschko, the former boxing champion, is also expected to run, as is the oligarch Petro Poroshenko, one of Ukraine’s richest men, who made his billions from chocolates. He currently leads the opinion polls.

Ms Tymoshenko was freed from prison on the day that Mr Yanukovych disappeared, leaving behind his vast estate with its private zoo and moored galleon on the edge of the capital. On Thursday, wandering through the Maidan, now a shrine to those killed and injured during the protests, Nataliya Dudyk, 32, recalled: “I was here when they brought Yulia from jail. There was some booing that night, which she didn’t expect. There’ll be a lot more booing if she comes here again.”

The teacher continued: “I am here because my cousin, Pyotr, was shot dead by the Berkuts [riot police]. We all wonder whether all these young people dying was actually for something worthwhile. We don’t want [the] same people who ruined the country staying in power. People are confused and upset, what’s happening here, with the Russians, with Crimea. That’s why they are starting all kinds of strange campaigns, it’s a sign of a damaged society. We need stability and peace in Ukraine, the problem is we really don’t know if that’s going to come.”