KIEV, December 21. /TASS/. Ukraine and Russia must conclude all agreements regarding transit of Russian gas and settlement of mutual claims before December 29, Executive Officer of Naftogaz of Ukraine Yury Vitrenko said on Satirday.

"We must sign everything before December 29 so that there will be transit from January 1," he said. Vitrenko called it "a very difficult task," emphasizing that the Ukrainian side will "work hard on this."

Vitrenko noted that it was "about new agreements on European principles," the preparation of which involved "international lawyers on both sides."

Naftogaz will also be included in the agreement, he said. Representative of Naftogaz said that separate agreements will be concluded between the Gas transmission system operator of Ukraine and Gazprom, between Naftogaz and Gazprom on organizing gas transportation, as well as between Naftogaz and the Gas transmission system operator of Ukraine.