Kiev  - Ukrainian President Viktor Yushchenko and Prime Minister Yulia Tymoshenko, theoretical political allies, are in open conflict over the development of Azov Sea natural gas fields by a US company, Korrespondent magazine reported Friday.

Yushchenko in remarks to reporters accused Tymoshenko, his direct subordinate, of attempting to sabotage a major energy development project for the purposes of political grandstanding.

Tymoshenko and Yushchenko together led Ukraine's 2004-2005 pro-democracy Orange Revolution. Currently serving as Prime Minister, the Tymoshenko technically is Yushchenko's direct subordinate.

Tymoshenko's recent charges of corruption in a planned 200 million dollar project led by US-headquartered Vanco Energy International are unfounded, and undermine Ukraine's hopes to be seen internationally as a reliable business partner, he said.

Vanco heads a consortium of companies that in February won a lease to develop oil and gas fields in Ukraine's energy-rich Azov Sea.

The project if successful could over its course of operation be worth tens of billions of dollars, and go far towards freeing Ukraine from dependance on oil and gas imports from Russia, Yushchenko has said.

Tymoshenko in remarks Monday claimed that Vanco won the tender unfairly, that its partners included Russian and Ukrainian oligarchs, and that the entire intent of the project was to transfer control of the oil and gas fields "to shadowy business interests."

Yushchenko's direct response to Tymoshenko's claims marked the most open conflict yet between the two politicians over a major economic issue.

Vanco executives on Thursday made public the identities of most of the shareholders in the project. Russian and Ukrainian tycoons were teaming up with Vanco in a seemingly legitimate energy play, a Channel 5 television analysis concluded.

The row between the two Ukrainian politicians raises questions over the reliability of the pro-Europe direction of Ukraine's parliament, as an alliance between MPs loyal to Tymoshenko and Yushchenko respectively currently control a razor-thin two-seat majority in the 450-seat.

Though both proponents of a pro-Europe/pro-NATO Ukrainian foreign policy, Tymoshenko and Yushchenko differ substantially on domestic economic policy.

Yushchenko, a former national bank head, favours monetary conservatism, attracting foreign investment, and conciliation with Russian business interests.

Tymoshenko, a former natural gas tycoon, favours manipulation of the national currency to improve domestic standard of living, direct government intervention in consumer goods markets, and because of their alleged corruption minimal links with Russian business. (dpa)