Ukraine has announced it would not to allow the transit of goods from Transdniester unless they were cleared by Moldovan customs.
Transdniester separatist leaders said the new rules amounted to "an economic blockade" and said Transdniester was pulling out of talks on solving the conflict with Moldovan authorities.
Moldovan officials, who have no control over the border posts between Transdniester and Ukraine, have long tried to persuade Kyiv to permit Moldovan customs officers to operate on the Ukrainian side of the border to stifle contraband.
Kyiv initially accepted the request in September 2001, during the rule of former President Leonid Kuchma, but expelled the Moldovan officials after less than 24 hours.
Ukraine's current move is seen as an attempt by the pro-reform government of President Viktor Yushchenko to secure an invitation to join the World Trade Organization, of which Moldova has been a member since 2001.
RFE/RL Belarus, Ukraine, And Moldova Report
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