KIEV, Jan. 20 – President Viktor Yushchenko on Sunday warned Prime Minister Yulia Tymoshenko’s government against revisiting a key natural gas agreement with Russia, saying the plan may backfire and spread chaos on the domestic gas market.

Yushchenko’s comments come days after the government pledged to renegotiate the agreement, perhaps towards either lowering gas prices or increasing tariffs that Ukraine charges Gazprom for gas transit.