However, Rehn said Montenegro and the region's other states in the region have "a concrete European perspective," and that the EU could conclude an association treaty with Montenegro this year.
Rehn also stressed that Montenegro will not be affected by the EU's decision to freeze association talks with Serbia. The EU took that step because of Belgrade's failure to comply with demands made by the UN tribunal investigating crimes committed during the Balkan wars of the 1990s.
Rehn also urged Serbia and Montenegro to start talks soon on the "practical terms" of what he hopes will be a "velvet divorce."
Rehn was speaking a joint news conference with Montenegrin Prime Minister Milo Djukanovic, who was on his first visit to the seat of the EU since the independence referendum on May 21.
Official preliminary results showing 55.5 percent voted "Yes" to independence, just a little higher than the 55 percent that the EU and local authorities had agreed was needed for the referendum to succeed.
