Ukraine has asked Russia to help upgrade its gas transit system, Ukrainian Prime Minister Yulia Tymoshenko said Wednesday, after a European Union deal with Kiev to modernize Ukraine's pipelines angered Moscow.

Ukraine has asked Russia to help upgrade its gas transit system, Ukrainian Prime Minister Yulia Tymoshenko said Wednesday, after a European Union deal with Kiev to modernize Ukraine's pipelines angered Moscow.

"We have invited Russia as one of the main partners to modernize the Ukrainian gas transportation system," Tymoshenko said at a joint news conference with her Russian counterpart Vladimir Putin.

"I think that such modernization can be conducted jointly," Tymoshenko said following a day of talks between the two leaders.

Last month, Ukraine signed an agreement with the E.U. paving the way for much-needed foreign investment in its dilapidated gas pipeline network, which carries 80% of Russian gas exports to Europe.

But the deal drew immediate fire from Putin, who called it "unprofessional" amid Russian complaints that Moscow had been left out.