Ukraine justice minister in state of emergency warning
Ukraine's justice minister has warned anti-government protesters occupying her ministry she will call for a state of emergency if they do not leave.
Olena Lukash told local media she would ask the National Security and Defence Council to introduce the measures.
The ministry became the latest government building to be occupied on Sunday, with protesters setting up bags of snow as barricades outside.
Unrest and occupations of municipal buildings are spreading across Ukraine.
Buildings have come under attack even in eastern areas, which have traditionally had closer ties with Russia and where President Viktor Yanukovych has enjoyed strong support.
The crisis was sparked by the president's decision not to sign a deal with the European Union, and has escalated with the deaths of four activists in recent days.
Correspondents say protesters entered the justice ministry building in the capital without resistance.
"The seizure of the Ministry of Justice is a symbolic act of the people of the uprising. Now, these authorities are stripped of justice," one protester told reporters.
One of the organisers of the occupation, who gave his name as Oleg, told the Associated Press news agency: "We are not going to do any hooliganism, or have anyone hurt. We are peaceful people, we are for justice."
But Ms Lukash told Inter TV channel: "If the protesters do not leave the justice ministry building... I will ask the National Security and Defence Council of Ukraine to impose the state of emergency."
The minister is an ally of President Yanukovych and involved in the ongoing negotiations between the government and protest leaders.
She said she would be "forced to turn to the Ukrainian president with a request to stop the negotiations unless the justice ministry building is vacated without delay and the negotiators are given a chance to find a peaceful solution to the conflict".
Last week, the parliament of the Crimean Autonomous Republic - seen as a staunch supporter of Mr Yanukovych - also urged the president to declare a state of emergency.
The BBC's David Stern in Kiev says it is not clear what such a measure would involve, but could entail the army being deployed.
The government has previously insisted it would not resort to the army, a measure our correspondent says would likely further antagonise the protesters and worsen the violence.
The parliament is due to meet for an extraordinary session on Tuesday, but the speaker has previously said a state of emergency will not be under discussion.
The EU delegation to Ukraine has called for the government to abide by promises it makes to protesters, and to revoke the protest laws.
In a statement, it expressed concern over reports of human rights abuses, and called on protesters to remain peaceful and distance themselves from violence.
The EU's enlargement commissioner Stefan Fule is returning to Kiev on Monday for talks with both sides on ending the crisis.
Street protests began in Kiev in November, after President Yanukovych announced he would not sign the long-awaited EU free trade agreement.
The protesters were further angered by the introduction of new laws last week aimed at cracking down on unrest by banning tents being put up in public places and the wearing of helmets and masks.
The opposition is demanding that the EU deal be signed, political prisoners - including former Prime Minister Yulia Tymoshenko - freed and the new laws repealed.
The fresh unrest comes after opposition leader Arseniy Yatsenyuk rejected President Yanukovych's offer to appoint him prime minister, saying the key demands must be met.
Although the protest movement - the EuroMaidan - is largely peaceful, a hardcore of radicals have been fighting battles with police away from the main protest camp in Kiev's Maidan, or Independence Square.
The unrest is now spreading further into the country's east, which is seen as Mr Yanukovych's support base.
Unrest was also reported across the country, with protests and at least a dozen attempts - some successful - to seize government buildings.
Towns and cities affected include: Zaporizhzhya and Dnipropetrovsk in the south-east, Cherkasy, south of Kiev: the main western city of Lviv: Chernihiv and Sumy in the north and Odessa on the Black Sea coast.