Ukraine's state company Naftogaz Ukrainy will tighten security of the country's gas transportation system following an explosion at the Urengoi-Pomary-Uzhgorod trunk pipeline in the Poltava region.

"The situation is very alarming. It was a very strange coincidence of circumstances. We will do all we can to tighten security at all of the gas transportation system's facilities," Naftogaz head Andriy Kobolev wrote on Facebook.

An explosion went off on the Urengoi-Pomary-Uzhgorod gas pipeline in the Lokhvytsia district of Poltava Region at about 1400 June 17. No injuries were reported. The law enforcement services said a subversive act could be involved.