Violence, blood, riots, and the rhetoric of betrayal returned to the heart of Ukraine on Monday.

Early in the day, activists from the right-wing opposition, random citizens, far-right Svoboda party members, and Right Sector militants blocked the streets of Kiev and the square around the nation’s parliament to protest constitutional changes being discussed inside. While lawmakers voted on a decentralization bill, in accordance with February’s Minsk ceasefire agreement, tensions boiled over both inside the parliament and out on the capital’s streets. Clashes, including a grenade attack on parliament itself, resulted in at least one death, dozens of severely injured police, and hundreds of casualties. A government official later said a detained suspect was a Svoboda member, and identified the dead policeman as a 25-year-old national guardsman.

Protest leaders echoed the heart of the conflict inside parliament, between Ukrainian politicians supporting the ceasefire deal with Moscow and those who opposed giving any authority to rebel governments. At the head of the lines, the Right Sector, a militant movement that called for a third revolution at a big gathering last month on Kiev’s main Maidan Square that included armed protesters among the 1,000 or so demonstrators.

On Monday, even more armed people were on the streets. As their representatives in parliament warned decentralizing the state would allow pro-Russian separatist groups to gain power, aggressive men in black masks in the front rows of protests outside Verkhovna Rada—Ukraine’s state parliament, known as the Rada—pushed police and tossed smoke grenades.

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Inside, tensions peaked at 11 a.m., when 50 lawmakers blocked the speaker’s tribune from delaying the time for the vote. Both sides accused each other of being pro-Russian and living with a Soviet mentality. Radical Party deputies drummed with plastic bottles, thumping their shaming of the country’s leadership. Party members screamed that Europe betrayed Ukraine, “as they did during Hitler’s times” and even brought up Vladimir Lenin’s quotes to castigate the pro-presidential parties. Ex-Prime Minister Yulia Tymoshenko said the bill was “neither a road to peace, nor to decentralization.” Tymoshenko opposed the measure, which was submitted by President Petro Poroshenko early this summer. “Our job is to bring the peace negotiation back on the right track by our ‘No’ vote—that would give us peace and not an illusion of peace.”

Even one of the most liberal parties, Samopovich, did not support the vote. Leader Oleg Berezyuk called the bill “a rape of the constitution” and a “betrayal of national interests.” No deputy from Tymoshenko’s Batkivshchyna party voted in support of decentralization. But the bill was approved by majority of the parliament: Of 368 lawmakers, 265 supported the bill at Monday’s session.

Moments later, a loud blast was heard outside, and black smoke crawled up the parliament wall. Someone had thrown a grenade at the thick throng of riot police. Bleeding and limping, dozens of cops rescued each other from the bloody scene. On Facebook, Anton Herashchenko, adviser to the interior minister, wrote that it was a combat grenade and that as many as 30 servicemen were severely wounded. Heavy lines of police struggled to push protesters back, away from Rada, as the square sank into smoke and tear gas.

By 4 p.m., the number of injured increased to 100 police, Kiev Mayor Vitali Klitschko told local TV reporters. “According to my information, some people died in clashes outside Rada,” the mayor said. By early evening, government officials counted 122 among the wound.

The war on the east was killing dozens of their troops every week, and it was just as painful for Ukrainians to see their servicemen being killed in the heart of their capital, too. Speaking Monday, Yuriy Lutsenko, of Poroshenko’s party, told parliament that they needed to support the “anti-Putin” coalition, and then referred to his opposition as “those sick with Bolshevism in their spine,” insisting that decentralization was what Maidan protesters were demanding “in order to bury the corpse of the USSR.”

Karen Madoian, of the EU project Support to Justice Sector Reforms in Ukraine, told The Daily Beast that Poroshenko’s bill was far from ideal, but Ukraine had no other option, as it was obliged to amend its constitution as part of the Minsk ceasefire. “Otherwise, we would not be backed by the West,” Madoian said. “I think Poroshenko has demonstrated to the Western partners that the majority in the parliament is under control. But I really doubt he will be able to get the majority vote of 300 MPs next time. Today, it was just a preliminary voting.”