Thousands of protesters in Kiev's Independence Square raised their hands to signify they would continue their demonstrations until the government met their demands, the Los Angles Times reported.
Yanukovych had rejected most of the opposition's demands. He did, however, agree to release 100 people detained since Sunday. He also promised the parliament would meet next week to consider canceling a number of laws that limited freedom of speech and assembly and set prison terms of up to 15 years for anyone participating in mass demonstrations.
On Thursday, Yanukovych rejected protesters' demands to call for early elections, the resignation of the cabinet and changes to the constitution that would establish a parliamentary republic with limited presidential powers.
Opposition leaders were also critical of a decision by Yanukovych to name Andrei Klyuyev head of the presidential administration, Russia's RIA Novosti news agency reported.
Klyuyev, a long-time Yanukovych ally, had headed the team negotiating with the protesters.
Opposition critics said Klyuyev was most likely appointed to end the protests.
Sergei Sobolev, head of parliament's opposition party Batkivshchyna, said he believed Klyuyev "remains committed to the option of force" to resolve the crisis.
Klyuyev replaced Sergei Lyovochkin, who resigned unexpectedly last week.
In presenting the proposed compromise to the protesters in Independence Square, opposition leader Vitali Klitschko, a former heavyweight boxing champion, urged activists to stick to a truce while Yanukovych carried out a potential compromise aimed at ending violent clashes with police, Ukraine's Espreso TV reported.
But demonstrators whistled as he spoke, expressing skepticism Yanukovych would keep his side of the bargain, and began erecting fresh barricades around their camp in central Kiev in the early hours Friday.
The demonstrators said they would expand the protest zone into Grushevsky Street, in downtown Kiev, and into European Square.
Opposition leaders agreed to follow the protesters' decision, but said they would continue talks with the government.
The protesters barricaded themselves inside the Agrarian Policy Ministry on Khreschatyk Street, a senior member of the opposition told Interfax-Ukraine.
"People will keep warm in the building," said the source, whose name wasn't reported.
The protester defiance came amid growing reports and evidence of brutality by riot police and other security forces, including beatings and stabbings by police of protesters and random people.
A video published Thursday by independent newspaper Ukrainska Pravda shows a male activist stripped naked except for boots in 14 degree Fahrenheit temperatures by a group of officers from the feared Berkut riot police, a special unit of the Ukrainian militia within the Ministry of Internal Affairs.
The video, also posted on YouTube, shows the naked man standing on a snow-covered street being forced by a police officer to be photographed while several other officers looked on.
Another officer is seen grabbing the man by the back of the neck, forcing him to hold an ice scraper, then slapping him on the head and kicking him as he directs him into a police bus.
Welts can be seen on the man's back as he climbs into the bus.
The Interior Ministry, which oversees the riot police, issued an apology, calling the treatment an "inadmissible action," and said the incident would be investigated.
Unrest also spread beyond Kiev, the capital, to several other cities, including Lviv and Rivne in western Ukraine and Cherkasy in central Ukraine.
U.S. Vice President Joe Biden urged Yanukovych to defuse the spiraling standoff, warning "further bloodshed would have consequences for Ukraine's relationship with the United States," the White House said.
German Chancellor Angela Merkel said she was "furious" about the worsening violence and the government's handling of it, and called on Yanukovych to respect law and basic rights.
A top EU official, Stefan Fuele of the Czech Republic, was to arrive in Kiev Friday and EU foreign policy chief Catherine Ashton is to visit Kiev next week, the 28-member bloc said.