Ukraine's president has met his rival, PM Viktor Yanukovych, as a bitter power struggle between the two men sent the country deeper into political crisis.
Mr Yanukovych said the president's move was unconstitutional
The PM said earlier President Viktor Yushchenko's bid to take control of 40,000 interior ministry troops meant a "use of force scenario" had begun.
The two leaders have been locked in their power struggle for months.
The EU has urged both parties to settle the deepening crisis though negotiation and not resort to violence.
They held three hours of talks, described by the president's spokeswoman as "constructive".
Irina Vannikova said the talks, which also included opposition leader Yulia Tymoshenko, parliament speaker Olexander Moroz and Security Council head Ivan Plyushch, would resume at midday (0900 GMT) on Saturday.
The row over control of the interior ministry special troops comes a day after riot police - acting in defiance of the president - seized the offices of sacked prosecutor general Svyatoslav Piskun.
They were acting on orders issued by Interior Minister Vasyl Tsushko - an ally of Mr Yanukovych - after President Yushchenko sacked Mr Piskun.
The crisis has been deepening since April, when Mr Yushchenko dissolved parliament and called a snap election. Mr Yanukovych and his governing coalition had initially rejected the move but later agreed in principle with the president to hold early elections.
The president originally said the vote would be held in May, but later moved the date back to 24 June after thousands of protesters from both sides took to the streets.
Speaking to a cabinet meeting, the prime minister denounced Mr Yushchenko's attempt to wrest control of the 40,000-strong force.
"Taking such decisions without consulting the government is inadmissible," he said.
"I think this seriously aggravates the situation."
Mr Yanukovych said the presidential decree had violated constitutional provisions placing the troops under the government's control. Mr Yushchenko is head of the army.
"What does all this mean?" he asked.
"This means that the 'use of force scenario', which we have been discussing constantly, has begun."
Interior Minister Mr Tsushko said he would ensure order, but accused the president and his supporters of driving Ukraine towards civil war.
The interior minister sent troops to the chief prosecutor's office
"It is a part of the president's entourage, whom I call the junta, which is pushing us towards civil war," he told Ukrainian TV.
"This is terrible, because we all want a peaceful life."
The BBC's Steven Eke says the language is ominous, but it remains to be seen whether it is more about posturing, than any real possibility of unrest.
Until now, our correspondent says, the political crisis has been played out in the courts and largely unproductive parliamentary wrangling.
The European Union issued an appeal "to all those with political responsibility to distance themselves from action which could result in any further escalation of the dispute, and in particular the use of armed security forces".
Mr Yushchenko had dismissed Mr Piskun for refusing to give up his seat in parliament, as required by law.
But the prosecutor general said he was sacked because he had resisted a presidential order to take action against three Constitutional Court judges.
The judges had refused to step down after being dismissed by President Yushchenko earlier in April.
Mr Tsushko described the sacking as "an attempted coup".
Mr Yanukovych and his supporters had opposed Mr Yushchenko's call for elections when he dissolved parliament in April.
The president had accused the prime minister of trying to usurp his power by illegally luring pro-Western lawmakers over to his coalition to increase his parliamentary majority.
The pair have been bitter rivals since Mr Yushchenko successfully overturned a disputed presidential election result in 2004, after mobilising thousands of supporters in central Kiev to protest against Mr Yanukovych's claim of victory.