MOSCOW, June 27 ??“ RosUkrEnergo, a Swiss-registered gas trader thought to be controlled by Gazprom, will buy and store in Ukrainian underground gas tanks 5.2 billion cubic meters of gas before the winter, a shareholder said.

The comment shows RosUkrEnergo has been trying to calm fears that Ukraine may have a shortage of gas during the upcoming winter as Naftogaz, the national gas company, owed $700 million to the trader.