All supply of natural gas to debt-ridden Kremikovtzi steel plant was stopped as of 12.43am on May 15 2009, Bulgarian-language Dnevnik daily quoted Tsvetan Bankov from the plant.

The termination of deliveries came after Kremikovtzi missed its 2pm deadline on May 14 for paying its debt to state-owned gas company Bulgargaz.

Deliveries were not cut off immediately because the Economy Ministry, who has shares in the plant, managed to negotiate a postponement with Bulgargaz after one of Kremikovtzi's labour unions said that the steelworks was close to securing a deal to keep it operational and allow it to pay for gas deliveries.

Despite this, supply was cut off a day later because of the 105 million leva debt accumulated by the plant, and the 10 million leva monthly losses incurred by the gas company and the country's state-owned power grid operator NEK.

According to experts, cutting off supplies would mean the end of the plant because vital production units would be unable to resume operation even if supplies are restored.

While Bulgargaz was terminating deliveries, Kremikovtzi's workers protested against the closure of the plant outside the Economy Ministry. Police had to intervene and restore order after workers tried to invade the building. Two protesters were detained.

According to private national bTV channel,  the workers headed back to the plant - in the eastern end of the city - with the intention of "winning it back from the traitors".