Ukraine’s largest steelmaker, Metinvest, has issued a call for employees in the Donetsk region to become “volunteer warriors” and protect local citizens against Kiev anti-terrorist operations.

Many steelworkers took to the streets in their work overalls and helmets and patrolled the streets alongside local law enforcement Sunday. The men, unarmed, are trying to keep public order and prevent violence, looting and vandalism. On the first patrol night, 120 metallurgists patrolled the streets.

“We must disarm and sit down at the negotiating table. Only then will our fellow citizens be completely safe," Yuri Ryzhenkov, CEO of Metinvest, said in a statement.

The company issued a statement Saturday that urged workers to join the local militia, but stressed that heavy equipment and weapons need to be abandoned.

“People need to feel that it’s not just police and people, as it has been in different cities in our country the past four months, but that it is people WITH the police,” Ryzhenkov explained in another statement issued Monday.

"People are paying attention and thanking us for our joint work with law enforcers. Support for police is especially needed after the recent events in our city,” Sergey Eliseev, a worker at the steel company said, Russia’s Vesti-24 television reported on its website.

Mariupol has been a hotbed of violence since clashes erupted between pro-Russian forces and 'anti-terrorist' campaigns led by Kiev.

“Each man defends his city, his home, and his family. Our presence on the street is peaceful and brings calm to residents,” said Eliseev.

Defending his steel empire

Metinvest, Ukraine’s largest steelmaker, is owned by the country’s wealthiest richest businessman, Rinat Akhmetov, who has a fortune estimated at $11.8 billion. Akhmetov reportedly struck a deal with local police to bring order to the city, and has also called for Kiev’s military to be kept out of Mariupol.

A fellow billionaire and governor of Dnepropetrovsk, Igor Kolomoisky, praised Akhmetov for his efforts to keep Kiev’s armed forces at bay and preserve the unity of Ukraine as a country.

“He fights with all his resources, trying to keep Donbass with Ukraine,” Kolomoysky said, Vesti-24 reported.

The coup-imposed government in Kiev said that they were “surprised” by Metinvest’s statement.

“In fact, Akhmetov’s statement is a demand to Ukraine to stop the anti-terroristic operation and call off our forces. This call will not just fail to fix the situation in the Donetsk region, but also spread this infection across Ukraine,” Sergey Pashinsky, acting head of the president’s administration, said in Kiev.

Akhmetov has previously said he remains committed to his investments in the region. The company’s production centers are located in the eastern and southern regions of Ukraine. The most recent annual report on the holding’s website shows $31 billion in group assets and $23.5 billion in revenue in 2013.

Workers at Metinvest plants recently received a 20 percent wage increase as a result of a recent miners’ strike in late April.