Russian gas giant Gazprom accused Ukraine on Monday of tapping about 100 million cubic meters of gas intended for European clients after the company halted gas supply to Ukraine in a grueling dispute over the gas price.

Speaking at a press conference in Moscow, Gazprom deputy chairman Alexander Medvedev said Ukraine illegally tapped about 100 million cubic meters of gas worth more than 25 million U.S. dollars following the company's cutback on gas supply to Ukraine.

"If siphoning continues on such a scale, the stolen amount will be quite significant," Medvedev said.

Gazprom cut down exports of gas to Ukraine by 120 million cubic meters a day on Sunday after Kiev shrugged off Moscow's demand to more than quadruple the gas price.

Medvedev said the company has invited an international audit company to monitor the situation so that "there would be independent measurements, not only our documents."

Gazprom provides about half the gas consumed in the European Union and 80 percent of that amount is sent through pipelines that cross Ukraine.

Some central European countries, such as Poland, Hungary and Austria, have borne the brunt of a gas cutback from Gazprom, reporting drops in pressure in gas deliveries from Russia.