Ukraine's embattled president has offered a string of concessions to the protesters occupying central Kiev. But the package is unlikely to bring an end to the conflict, which has already claimed at least three lives in the capital.

After lengthy negotiations with opposition leaders, Viktor Yanukovych saidon Friday he would reshuffle the government and modify draconian laws against demonstrations. But the key demand, for snap parliamentary and presidential elections, does not appear to be on the table, nor is there any suggestion that the president is ready to sack his hardline prime minister, Mykola Azarov.

In central Kiev, anti-government activists who occupied another government building overnight, were unimpressed with the concessions. At the barricades near the Dynamo Kiev football stadium, protesters resumed their assault on police lines overnight, with barricades of burning tyres lit and projectiles fired at riot police using a giant catapult. The police doused the fires with water cannon but were not responding with force.

As the night continued, the majority of those at the barricade were the hardcore of the protest movement, dressed in combat fatigues and ready for violence.

Earlier in the day, there had been a more mixed crowd at the barricade. Natalia, a 50-year-old engineer from the east of Ukraine, had arrived on Thursday, bringing helmets and medicines to the barricades. "I came here to defend the future of my children. We have no future if we are ruled by this criminal," she said.

Sergiy, a 20-year-old student wearing helmet and gas mask and wielding a wooden stick and a shield fashioned from a traffic sign, said he thought negotiating with the president was pointless: "This bastard is only playing for time, but the country has already risen up against him."

He claimed that a friend of his was beaten up by men in civilian clothes after being seized from the protest, then taken to a forest and stripped naked.

There were many such stories. A video of one incident where riot police humiliated a naked protester and took trophy photographs has circulated widely, sparking further outrage. Mikhailo Gavrilyuk told journalists he was seized on Wednesday as he attempted to help an injured fellow protester. "They dragged me off and started beating me. They threw me to the ground, put their legs on my head and photographed me. They took turns to beat me, and someone suggested they should cut off my hair, which they then did with a knife."

He later had his clothes taken away and was taken, naked, to a police station, he said. The interior ministry has announced an investigation into the incident, but Gavrilyuk said he expected fellow protesters to exact "terrible revenge".

The changes to the laws and government reshuffle are expected to take place at an emergency parliamentary session scheduled for next Tuesday. But as the weekend approached, Yanukovych faced not only a stand-off in Kiev but also a breakdown in his authority across the west of the country, where activists have seized administrative buildings in a number of cities, and built barricades around them. The interior ministry claimed that a policeman had been shot while walking home, unarmed, on Friday night. Details of the incident, and whether it was linked to the protest, were not forthcoming.

The trio of opposition political leaders who took part in discussions with Yanukovych have come under pressure to take a firmer stance against the government and withdraw from negotiations. Former heavyweight boxer Vitali Klitschko on Wednesday promised to "go on the attack" if Yanukovych did not call elections within 24 hours, but is now calling on protesters to hold a ceasefire, uneasy about being seen as responsible for escalating the situation. However, he said on Friday that the protest would not wane without Yanukovych's resignation.

Klitschko said: "A month ago this would have been over with the firing of Zakharchenko [the interior minister]. Two weeks ago people would have been satisfied with the dismissal of the government. Today people will only accept the resignation of the president."

The European commission official Stefan Füle travelled to Kiev to meet with Yanukovych on Friday and urged him to refrain from further violence. Füle was instrumental in arranging an association agreement between the European Union and Ukraine - that Yanukovych backed out of at the last minute - sparking the initial round of protests two months ago. In France and Germany, the Ukrainian ambassadors were summoned by the respective foreign ministries, who expressed concern over the violence.