Kiev, Ukraine (CNN) -- Violent clashes between anti-government protesters and police continued in the center of Ukraine's capital, Kiev, overnight into Tuesday.
Demonstrators have been rallying since the weekend in defiance of new laws that limit the right to protest.
The Interior Ministry said Tuesday that more than 30 protesters had been detained and 119 police officers injured since Sunday afternoon, when the clashes began.
The city health care department reported 122 injured and 50 hospitalized. The number injured is probably higher, as many people reportedly turn to medical volunteers for help rather than official services for fear of consequences. Protest organizers said those treated in hospitals are questioned by police and registered as participants of mass protests, which may lead to arrest and criminal charges.
Protesters and police have accused each other of violence.
The controversial new protest laws go into effect Wednesday, raising concerns they could be used to put down demonstrations.
Opposition politicians have objected to the way that lawmakers loyal to Ukraine's pro-Russian President Viktor Yanukovych pushed the legislation through parliament last week by a show of hands.
The new laws include provisions barring people from wearing helmets and masks to rallies, from setting up tents or sound equipment without prior police permission, and from traveling in convoys of more than five vehicles without authorization.
A separate Interior Ministry order allowing riot police to use firearms came into force Tuesday, according to the official Ukrainian legislation website.
The latest clashes are an escalation of weeks of largely peaceful public protests prompted by Yanukovych's decision in November to spurn a planned trade deal with the European Union and turn toward Russia instead.
Yanukovych's official website said Tuesday that a newly formed government working group had met to discuss the political crisis and that it had been joined by opposition leader Vitali Klitschko, a former champion boxer.
However, a news release from Klitschko's UDAR party denied that he had taken part in the meeting, saying he had gone to the presidential administration building only to speak with Yanukovych and left when the President was not available.
Russian foreign minister urges dialogue
Russian Foreign Minister Sergey Lavrov warned at an annual news conference Tuesday in Moscow that the situation in Ukraine was "getting out of control" and pointed the finger at some opposition leaders.
"Now there are problems, attacks on the police, Molotov cocktails. This is beastly. It is an absolute violation of all European standards," he said.
He called on all parties involved to resolve the situation through dialogue.
Lavrov suggested the interference of some European Union countries in Ukraine's internal situation was not helping. Russia is doing all it can to support the stability of the country, he said.
Ukraine's Institute of Mass Information, an organization promoting media rights and freedom of speech, said 34 journalists had been injured while reporting on the clashes.
There are also reports that hired thugs, armed with baseball bats and sticks, were trying to scare people in the city center.
Jailed opposition leader Yulia Tymoshenko said in a prepared statement Monday that she would be on the streets with the protesters if she were free.
She accused the Ukrainian government of having driven "peaceful and optimistic Ukrainians" into a corner by taking away their rights to protest. "Those standing on the front lines for Ukraine are heroes!" she said.
Concerns about 'anti-democratic legislation'
U.N. High Commissioner for Human Rights Navi Pillay on Tuesday described the violent clashes in Kiev as "very worrying" and said there was an urgent need for dialogue to avoid an escalation of violence.
Pillay also called on the government to suspend implementation of the new protest laws so they can be reviewed.
"I am particularly concerned by the potential that these laws have to curtail the right to freedom of expression and freedom of assembly, the right to information, the right of civil society to work freely," she said. "The laws also have the potential to result in impunity for human rights violations."
EU foreign ministers and foreign relations chief Catherine Ashton also expressed "deep concern" Monday about the legislation and called for a democratic solution to the political crisis.
The EU "calls on all actors to exercise restraint and on the authorities to fully respect and protect the peaceful demonstrators' right to assembly and speech, and the freedom of the press," it said.
The White House urged all sides to "immediately de-escalate the situation."
Caitlin Hayden, a spokeswoman for the U.S. National Security Council, called on Ukraine's government to repeal the "anti-democratic legislation signed into law in recent days," withdraw riot police from downtown Kiev and begin a dialogue with the opposition.
She said the United States would continue to consider additional steps -- including sanctions -- in response to the use of violence.
Russian gas deal
In December, despite weeks of protest by anti-government demonstrators, Yanukovych agreed to a deal with Russian President Vladimir Putin for Moscow to buy Ukrainian debt and slash the price Kiev pays for its gas.
The tumult in Ukraine goes to the heart of its future ties with Russia and the rest of Europe. Ukraine is split between pro-European regions in the west and a more Russia-oriented east.
The protests have unfolded since November 21, when Yanukovych changed his stance on the EU trade pact, which had been years in the making.
The demonstrators say an EU agreement would open borders to trade and set the stage for modernization and inclusion. Ukraine's government says the terms needed to be renegotiated to protect Ukrainians better.
Journalist Victoria Butenko reported from Kiev, and CNN's Laura Smith-Spark wrote in London.