KIEV, June 19 - Prime Minister Yulia Tymoshenko’s government challenged President Viktor Yushchenko late Wednesday by announcing it will not reinstate the production sharing agreement (PSA) with U.S. oil company Vanco Energy.

Oleksandr Turchynov, the first deputy prime minister and Tymoshenko’s closest ally, called a special government commission meeting late Wednesday to confirm the government’s controversial withdrawal from the PSA.