This was announced by Nashi Hroshi website, Censor.NET reports.
Pietukhov is in charge of the Ministry's Department of international law as deputy minister on European integration.
Before entering the ministry, Pietukhov used to work as director for corporate issues of the Karpatyhaz company between 2012 and 2015.
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The company announced in September it was preparing an international lawsuit against Ukraine. The claims concern "discriminatory" rent payments for oil and gas companies. They are set at 70 percent of the value of gas for the so-called cooperation agreements - projects in which the owners are the state Ukrhazvydobuvannia enterprise and private firms. One of such agreements regulates a project involving Karpatyhaz.
Karpatyhaz was found by Swedish company Misen Enterprises AB. According to Nashi Hroshi, it might be related to Ukrainian oligarch Firtash's holding.
In case Ukraine is sued in international courts, the Ministry of Justice is to choose defense attorneys.
After this information went public, Pietukhov announced on Facebook he would not be involved in this litigation.