Steelworkers employed by one of Ukraine’s richest men are patrolling some of the disputed eastern Ukrainian cities that have been occupied by pro-Russian insurgents.

The workers are from Metinvest plants, which are owned by billionaire Rinat Akhmetov, believed to be Ukraine's richest man. Unarmed patrols were spotted in the cities of Mariupol and Makeevka. Their involvement is intended to resolve conflicts in the region ahead of the May 25 presidential election. On Wednesday, Akhmetov said in a statement that Donetsk, the regional capital, must remain part of Ukraine, lest the country suffer economic consequences.

While insurgents, who call themselves the Donetsk People's Republic, continue to fight for more autonomy -- not only with recent referendums but also with the announcement of a parliament on Thursday -- they have made an agreement with steel plant directors and local police to improve security and vacate seized buildings, according to a Metinvest statement.

"A civil war is underway, and it's important for us to create a power bloc to successfully fight the Kiev junta," Yelena Korovkina, a member of the self-proclaimed parliament, said Thursday.

Steelworkers were deployed to at least five cities late Thursday, including Donetsk. The patrols in Mariupol and Makeevka had helped solve or prevent crimes, including robbery, police said.

Meanwhile, clashes were reported in eastern Ukraine Friday, including a firefight at a checkpoint held by Ukrainian national guardsmen near Mariupol.

According to the head of a militia group that supports Kiev’s interim government, a unit of pro-Ukrainian volunteers regained control of Velyka Novosilka, a city about 30 miles southwest of Donetsk, late Thursday.

On the diplomatic front, ad hoc talks on Ukrainian national unity in Kiev took place earlier this week between Ukraine and Russian officials. Pro-Russian separatists did not attend. British Foreign Secretary William Hague called the talks “clearly successful” despite reports of one session ending with accusations and grandstanding.

On Thursday, Russian President Vladimir Putin announced that Ukraine must pay in advance for Russian gas supplies starting next month. He cited Ukraine’s $3.5 billion debt for gas supplies -- a resource for which Ukraine is heavily dependent on Russia.

Ukraine said it would pay Russia if the country restores the price discounts that were in place before pro-Russian President Viktor Yanukovych was toppled in February after months of protests.

The next round of talks is expected to start on Saturday. Insurgents say it should take place in Donetsk and focus on the exchange of prisoners and the pullout of government forces.