Five people were killed in an ammonia explosion at the No. 1 Plant of PJSC Stirol Concern (Horlivka, Donetsk region), the prosecutor's office in Donetsk region has told Interfax-Ukraine.

"We have been informed that five people were killed, [and] information about the number of injured is being checked," the prosecutor's office said.

According to the prosecutor's office, the accident occurred at around 1400 on Tuesday. Rescuers are working on site of the accident at the moment.

According to preliminary findings, a gas leak occurred due to an ammonia pipeline failure.

The regional prosecutor's office also said that the accident is being investigated under Part 2 of Article 272 (violation of the rules for performing hazardous operations).

The press service of the State Service for Emergency Situations of Ukraine told Interfax-Ukraine that, according to preliminary information, three people were killed and seven were injured in the accident. Later on, two people died on the way to hospital or at hospital.

"An ammonia explosion occurred when a warm ammonia pipeline was being repaired," the State Service for Emergency Situations said.

At the same time, the press service of Horlivka Town Council reported that "according to preliminary data, 11 people were injured in the accident, and five of them died." Those injured were hospitalized in town clinic No. 3.

"According to the civil protection department, the accident poses no threat to the lives and health of town residents," reads the statement.

The press service of Ostchem reported on Tuesday that "on August 6, an emergency situation occurred at PJSC Stirol Concern – at 1430 during overhauls at the No. 1 Plant there was an ammonia blowout. The emergency rescue service of the concern completely mitigated the breakage within 20 minutes, but people were hurt in it. A special commission has started investigating the reasons for the ignition. There is no threat to the population."

Stirol is one of Ukraine's biggest chemical producers. Ostchem is a managing company that coordinates the strategy of six fertilizer companies belonging to Group DF of Dmytro Firtash, four of which are located in Ukraine: Stirol Concern, Severodonetsk Azot, Cherkasy Azot and Rivneazot.