BELGRADE, May 25 (Reuters) - Serbia should quickly establish a constructive new relationship with Montenegro following the smaller state's referendum vote to end their union, the U.S. ambassador to Serbia and Montenegro said on Thursday.
"There are moments in history and time when opportunities can be seized and right now this is one," Michael Polt said.
"But the real engagement has not yet begun. I hope and I trust it begins -- and certainly we will be pushing very hard for that -- very quickly after final results are announced."
Montenegro's mainly ethnic Serb opposition, which campaigned against independence in the referendum on Sunday, is seeking a re-run of the ballot in dozens of polling stations. Serbian Prime Minister Vojislav Kostunica has said he "will accept" the pro-independence vote, but only when final results are in.
Polt told Reuters in a telephone interview there was some concern about possible foot-dragging by Serbia on Montenegro, but "I trust that cooler heads and wiser heads will prevail".
He said Washington appreciated Serbia's problems. Talks on its European Union membership hopes are frozen over failure to deliver war crimes fugitive Ratko Mladic, and Albanian-dominated Kosovo province is driving for independence this year.
These challenges could be seen as "opportunities to be grasped very tightly" for the improvement of the Serbian people, Polt said. But he had "great concern they will not be seized".
NO CLEAR GOALS
Some Western countries are reluctant to put further pressure on Belgrade, worried about the government's fragility and the strength of the ultranationalist Radical Party.
"I don't lose a moment's sleep about the non-reformers," Polt said. His main concern was the lack of articulation "of where this government wants to take this country".
In U.N.-mediated talks on Kosovo, Kostunica's team so far seemed fixated on its determination to block independence.
"We are concerned that not enough attention is being given to the Serbian existence in Kosovo," he said. "What about real people? Belgrade keeps saying they care about what happens to the Serbs in Kosovo ... we need to get on with that and stop getting hung up over what it's going to be called."
Kostunica's government, a minority coalition relying on the unofficial backing in parliament of the Socialist Party of the late strongman Slobodan Milosevic, was failing to deal effectively with these major issues, the ambassador said.
A key coalition partner, the liberal G17 Plus party, has warned it will walk out on Kostunica and trigger a snap election if the EU talks are not resumed by the end of September -- implying that Bosnian Serb wartime commander Mladic will have to be in detention at the Hague war crimes tribunal by that date.
Polt seemed unimpressed by the party's four-month ultimatum.
He said he was disappointed at lack of credit given to deputy Prime Minister Miroljub Labus, who resigned on principle this month after the EU suspended talks saying he could not endorse policies that undermined his main objective for Serbia.
As for G17's deadline for delivery of Mladic, indicted for genocide in 1995, he said:
"I have torn up and thrown away my calendar. I take no deadline seriously ... Any discussion of future dates at this point is basically laughable."