On 14 April 1987, Turkey submitted its application for formal membership into the European Economic Community. The European Commission responded in December 1989 by confirming Ankara's eventual membership but also by deferring the matter to more favourable times, citing Turkey's economic and political situation, as well its poor relations with Greece and the conflict with Cyprus as creating an unfavourable environment with which to begin negotiations. This position was confirmed again in the Luxembourg European Council of 1997 in which accession talks were started with central and eastern European states and Cyprus, but not Turkey. During the 1990s, Turkey proceeded with closer integration with the European Union by agreeing to a customs union in 1995. Moreover, the Helsinki European Council of 1999 proved a milestone as the EU recognised Turkey as a candidate on equal footing with other potential candidates.