RIVNE, Ukraine (CNN) -- Camouflage-clad militiamen hoist AK-47 assault rifles to their shoulders and blast off a 21-shot salute.
As the muzzles flash, another squad of ultra-nationalist fighters chants, "Our hero is not dead. Glory to him."
A few yards away, a Ukrainian Orthodox priest swings an incense burner. A mother and father weep over the coffin of their dead son.
The killing of radical nationalist leader Oleksandr Muzychko, also known by his nickname "Sasha the White" was enough to make shaven-headed, hardened paramilitary men cry.
"He was like a brother to me and my comrades. But that bastard Putin murdered him," said Anatoly Valsyuk, as he choked back tears.
Valsyuk served under Muzychko, who was commander in western Ukraine for the "Right Sector," a recently formed alliance of right-wing and nationalist political parties and militia forces.
Ukraine's Interior Ministry said its special agents killed Muzychko Monday night here in the western city of Rivne as he resisted arrest. The Interior Ministry says he was a gangster.
But Right Sector leaders are calling for the Interior Minister Arsen Avakov to resign and face murder charges over Muzychko's death. They say the Avakov is one of Ukraine's corrupt old-guard politicians and that he and his men may even have been taking orders from Moscow.
Whatever the true details of his Muzychko's death, it is a sign that political partners in the new Ukraine may have old scores to settle -- divisions that Moscow may be poised to exploit.
Muzychko and the Right Sector are credited with playing a lead role in this winter's protests that toppled Ukrainian President Victor Yanukovitch. The nationalist paramilitary militias won admiration from many ordinary Ukrainians for their stiff discipline and determined street-fighting tactics.
Mourner Svetlana Bilyus, an English-speaking interpreter, had made the three-and-a-half hour drive from the capital to Rivne to be at the funeral Wednesday.
She said she met Muzychko only once, at the barricades around Kiev's emblematic Independence Square or "Maidan," the scene of the deadliest clashes between anti-government protestors and Yanukovitch's security forces in January and February.
"He was a national hero. He's an inspiration for millions of Ukrainian people, especially young people. He's a local Robin Hood," Bilyus said
Muzychko, 52, reveled in his tough-guy image. His Facebook page is plastered with images of him, crop-haired in combat fatigues giving a raised-arm, clenched fist salute. Others show him relaxing in his favorite Oakland Raiders cap and jacket.
According to his comrades, he led a small unit of Ukrainian nationalists to fight alongside Muslim Chechen rebels against the Russians.
In contrast, elderly women on the sidelines of his funeral attested to Muzychko's "Robin Hood" character. They said he and his men had campaigned heavily for better pension rights for old people across the region.
Paramilitary units under the umbrella of the Right Sector have sparked the alarm of Russian President Vladimir Putin. Putin says he fears that these nationalist groups, which he refers to as "fascists," will hunt down and attack ethnic-Russians living in Ukraine.
In the wake of the overthrow of the Yanukovitch regime, no such widespread incidents have been reported. But Putin used this as a pretext to forcibly annex the Ukrainian region of Crimea.
Now, according to the Pentagon, there are an estimated 30,000 Russian troops, armed with heavy artillery and tanks, massing along Ukraine's eastern border. The Ukrainian government puts the figure even higher.
U.S. and NATO officials say the Russians could roll into Ukraine any time, without warning in a bid to annex Russian-speaking areas of eastern Ukraine or even push into Trans-Nistria, a disputed enclave in the former Soviet republic of Moldova.
Ukrainian troops in Crimea opted not to defend their bases in the face of advancing Russian forces. Instead they surrendered naval, air and army facilities one by one or waited until they were overrun. Ukraine's Defense Ministry estimates up to 75% of the approximately 15,000 troops based there may have defected to the Russians.
But in an interview with CNN, the top national leader of Right Sector, Dmitry Yarosh said fighters under his command would not stand by if Putin ordered the Russian army into other parts of Ukraine.
"The Right Sector will do its best to launch a partisan, guerrilla war. The land will literally burn under the feet of the invaders. We will not be lambs to the slaughter. We will defend our independence by any means necessary," he said.
Despite fears Ukrainian government security forces could target other Right Sector leaders, Yarosh made the trip to Rivne to march alongside Muzychko's coffin.
He was flanked by black-clad bodyguards, one brandishing a Russian-made machine-pistol, the other a high-powered sniper rifle.
Yarosh, too, blamed Russian sympathizers within the Interior Ministry for killing Muzychko.
The popularity of Right Sector and Ukraine's radical nationalist groups was bolstered so significantly in the anti-government protests that Yarosh thinks he has a real chance at winning the presidency in elections in May. But he stresses personal power is not his main ambition.
"The presidential post is not the goal in itself. We understand we may win or we may lose. This post offers the possibility to bring quality and systematic changes to the country as well as the possibility to 'reload' the power structure so there is the change of elites not just a change of faces," Yarosh said.
But the rise of Right Sector is not only worrying Moscow but also some Western government officials. Some believe Right Sector is a safe haven for right-wing extremists and even Ukrainian neo-Nazis.
Such charges stem back partly to the legacy of Ukraine's nationalist, partisan forces before and during World War II. While it is true that Ukrainian nationalists sought the help of Nazi Germany to drive the Soviets out of Ukrainian territory, some later fell afoul of the Nazis and ended up in German concentration camps.
These days, Yarosh spends a lot of his time trying to dispel such fears. He has even appointed a Ukrainian Jew as one of his most trusted media and communications advisers.
"Right Sector is a nationalistic organization. But Ukrainian nationalism has nothing to do with the German Nazis or the Italian fascists," Yarosh said.
"We have always been and will always be against xenophobia, anti-Semitism and for Ukraine to have an independent nation where the rights of all the minorities will be guaranteed," he explained.
It's hard to argue with Yarosh as you meet the stare of his ice-green eyes.
But it's also easy to worry about Right Sector's true ideological leanings when you see the red-and-black flags, stylized insignia and other paraphernalia of its militiamen.
As an afternoon drizzle came down on Muzychko's funeral, tears snaked along the wrinkles of his father Ivan's face.
His mother Olena lowered a loaf of wholemeal bread into the grave -- a local tradition to ensure her son would not go hungry in the afterlife.
And dozens of men who once marched to Muzychko's command now filed past his grave, tossing handfuls of damp earth onto his coffin. In unison they vowed -- no surrender to the Russians.