Pro-Russian insurgents have retreated from government buildings in a major eastern Ukrainian city since steelworkers began citizen patrols, giving residents hope that a wave of anarchy was over.

Mariupol, the second-largest city in the Donetsk region, was one of the cities in the east where pro-Russian protesters seized control of government buildings.

Citizen patrols began earlier this week as Rinat Akhmetov, Ukraine's richest man, urged the steelworkers at his factories to help the police restore order.

Mr Akhmetov's company, Metinvest, initiated Thursday's agreement with steel plant directors, local police and community leaders on improving security in the city and vacating separatist-occupied buildings. A representative of the self-proclaimed Donetsk People's Republic, which declared independence on Monday, was also a party to the deal.

German Mandrakov, who was once the commander of Mariupol's occupied government building, said that his associates fled, while he was "forced" to leave the building they had controlled for weeks.

"Everyone ran away," he said, using a vulgar Russian word to refer to them as cowards. "Someone is trying to sow discord among us, someone has signed something, but we will continue our fight."

Metinvest has two steel plants Mariupol, a city of half a million people and an important port and industrial centre on the main road between Russia and Crimea, the peninsula annexed by Moscow last month.

The city saw heavy fighting in the past weeks, including a shoot-out outside a police station that left one policeman and several insurgents dead.

On Friday morning, several dozen Metinvest workers in overalls and helmets were clearing out the barricades outside the government building.