Sofia - The Bulgarian government on Thursday invited the world's largest steel concern, Arcelormittal, to take over the troubled Kremikowtzi mill.

"It is one of the world's best-known enterprises," Economy and Energy Minister Petar Dimitrov said, announcing the decision to call in the company of the India-born billionaire Lakshmi Mittal.

Lakshmi's younger brother, Pramod, already owns the majority stake

in the debt-ridden Kremikovtzi mill, near the capital Sofia, which went bankrupt in August.

Dimitrov said however that the government is negotiating the sale of its 25-per cent stake in Kremikovtzi with "other domestic and foreign candidates."

Investments in Kremikovtzi, a Communist era "giant," stumbled on expensive environment-protection measures which must be implemented as Bulgaria joined the European Union in 2007. The mill currently produces 70,000 tons of steel monthly, at less than half-capacity.

Production problems are bound to multiply after the Ukrainian Vorskla Steel canceled the supply of raw materials in a bailout deal agreed in August.

Vorskla director for Bulgaria, Victor Demyanyuk, however announced Monday it was terminating the deal with Kremikovtzi, saying its workers "became accustomed to holding strikes instead of working."

Labour unions at the mill held the most recent protest on Tuesday, when they demanded backlog salaries and a new investor to replace Pramod Mittal. (dpa)