KIEV, Feb. 19 - Ukraine's national oil and gas company Naftogaz Ukrayiny warned on Thursday that increasing debts from power producers and other firms for natural gas supplies jeopardize the company’s ability to pay Gazprom.

Under the gas agreement signed on January 19, Naftogaz faces a major penalty if the company fails to make the payment within the first week of the next month. Naftogaz apparently made the payment for January supplies before February 7.