He announced the Council of Ministers might decide to discontinue negotiations as early as Monday.
Opening archives and launching individual investigations stand for the extradition of Ratko Mladic, Zoebel told a conference on crimes committed in Foca in 1992, organised in Belgrade by the Humanitarian Law Fund.
"The Serbian government has slowed down cooperation with the Hague tribunal and we again don't know when Mladic is expected to be in The Hague and again deadlines are not being honoured," the ambassador said.
He added that in recent months Serbia's cooperation had been disappointing so much that the EU was considering the possibility of discontinuing negotiations on stabilisation and association.
Zoebel said it was unacceptable that Mladic, 10 years after the Srebrenica massacre, was still at large, had been receiving pension until a few weeks ago, and was still being harboured.
Although the crimes at Foca and Srebrenica are the darkest pages of Serbian history, there are still people who maintain that "Mladic and the Foca cutthroats are Serb heroes," said the ambassador.