* Yanukovich meets three opposition leaders
* Opposition seek concessions at Tuesday parliament session
* Activists briefly occupy justice ministry building
* EU voices concern over disappearances, reported torture (Adds Yanukovich meeting opposition, other detail)
By Richard Balmforth
KIEV, Jan 27 (Reuters) - Ukraine's Viktor Yanukovich held fresh talks with opposition leaders on Monday to prepare for a crunch session of parliament at which the president and his allies will be under pressure to make major concessions amid mass unrest.
A tough battle lay ahead at Tuesday's session with the opposition calling for concessions including the repeal of sweeping anti-protest laws, the dismissal of the government and an amnesty for all protesters detained in two months of unrest.
Ukraine's justice minister raised tensions by warning she would press for a state of emergency if protesters did not vacate a ministry building they had occupied overnight.
The protesters later left the premises, after defying police for several hours, but said they would return if there was no progress in parliament on Tuesday.
As the opposition leaders - boxer-turned-politician Vitaly Klitschko, former economy minister Arseny Yatsenyuk and nationalist Oleh Tyahnibok - met Yanukovich, the President's party set the scene for a rowdy session of parliament, saying they did not intend to yield any ground.
"The prime minister will not be going. Parliament tomorrow will not be voting for the resignation of the government," Mykhailo Chechetov, a spokesman for the Party of the regions, told Interfax news agency.
He said the Regions parliamentary faction would equally block any attempt to repeal the anti-protest legislation which Yanukovich loyalists rammed through parliament on January 16.
"We are categorically against changing these laws. What are we talking about here? A bandit must go to jail," he said.
OPPOSITION RALLY CALL
The Batkivshchyna (Fatherland) party of jailed opposition leader Yulia Tymoshenko, now headed by Yatsenyuk, called on its supporters to rally in Kiev's Independence Square on Tuesday in solidarity with opposition deputies in parliament.
"Come at 12 o'clock and support the deputies who are ready to take on themselves the responsibility for getting rid of these dictatorial laws," a statement said.
Yanukovich triggered the upheaval in November when he abruptly abandoned plans to sign association and free trade deals with the European Union, opting instead to tighten economic ties with former Soviet master Russia, and angering millions who dream of a European future.
The protest movement has since turned into a mass demonstration, punctuated by clashes with police, against perceived mis-rule and corruption in the Yanukovich leadership.
Several hundred people camp round-the-clock on Kiev's Independence Square and along an adjoining thoroughfare, while more radical protesters confront police lines at Dynamo football stadium some distance away.
That area remained calm overnight into Monday.
The occupation of the justice ministry building was the third such action in four days. Protesters occupied the agricultural ministry on Friday and only agreed to leave the energy ministry which they entered on Saturday after the minister warned their action could disrupt energy supplies in the country.
Justice Minister Olena Lukash said in a video statement: "If the justice ministry building is not vacated immediately, I will be forced to appeal ... to the Council for National Security and Defence with a demand that introduction of a state of emergency in the country be discussed."
A State of Emergency would limit movements of people and vehicles, ban rallies, marches and strikes, suspend the activity of political parties and introduce a curfew.
The unrest has spilled over into other regions of the country of 46 million people, including areas of eastern Ukraine and the south which are traditionally pro-Yanukovich.
Ukraine on Monday announced it would draw on another $2 billion of credit - adding to $3 billion already received for purchase of a bond - from a $15 billion bailout package offered by Moscow after the former Soviet republic walked away from the deal with the EU.
But though the Russian aid package will help Ukraine handle $8 billion of foreign debt this year and boost depleted reserves, this does not seem to be impressing thousands on the streets who are pressing for concessions from Yanukovich.
GOVERNMENT POSTS OFFERED
Yanukovich on Saturday offered top government posts to opposition leaders - the prime minister's job to Yatsenyuk and a deputy prime minister's portfolio to Klitschko - in his first concessions in two months of unrest.
But the opposition sees this is an attempt to divide them and are pressing for more. They are also want Yanukovich to agree to an early presidential election ahead of the due date of February or March 2015 - but this is something he could scarcely agree to since polls indicate his popularity has plummeted in the crisis.
Western governments have backed the opposition in denouncing the legislation, which places curbs on media as well as banning virtually all forms of protest, as anti-democratic.
In a statement on Monday, EU national envoys called on all sides "to revoke the whole package of legislative acts restricting the exercise of fundamental freedoms" and urged the government to keep its promises to the opposition.
Western governments are also expressing growing concern over the security situation in Ukraine amid reports of abductions, including by police, as well as the clashes between radical activists and police. EU foreign policy chief Catherine Ashton is due to visit Kiev on Thursday and Friday.
The United States has warned Yanukovich that failure to ease the standoff could have "consequences" for its relationship with Ukraine. Germany, France and other Western governments have also urged him to talk to the opposition.
Russia has stepped up its warnings against international interference in Ukraine, telling European Union officials to prevent outside meddling and cautioning the United States against inflammatory statements. President Vladimir Putin is due to visit Brussels on Tuesday for what promises to be a tense EU-Russia summit. (Additional reporting by Natalia Zinets and Pavel Polityuk; Writing By Richard Balmforth)