Officials who attended the meeting in Ljubljana said both sides took hard-line positions and there was little sign of a compromise.
Russia agreed at an OSCE conference in Istanbul in 2000 to withdraw its troops and military equipment from Transdniester. However, many are still in place and Russia argues that it will take several years to complete the withdrawal.
U.S. officials said Washington supports Moldova's position.
An OSCE official said another argument is continuing on whether there should be a reference to the Istanbul agreement in the final document of the current meeting in Ljubljana. Russia told the meeting it did not want a reference to the Istanbul agreement.