Serb Prime Minister Ivica Dacic has blamed the US for blocking a potential land-swap deal with Kosovo which, he says, could have ended the frozen conflict over ethnic Serb enclaves.

Speaking in Belgrade with German daily Frankfurter Allgemeine Zeitung (FAZ) on Monday (8 April), he said one potential solution for normalising relations would have been to give Kosovo control of a majority-Albanian region in the Presevo Valley in southern Serbia in return for Serbia's control of a majority-Serb region in north Kosovo.

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"I actually think that Serbs and Albanians could easily agree to a land swap. But that would not be acceptable to Washington. The view here is that this could lead to a war in Macedonia," he noted.

He added the Macedonian government created the risk of conflict between its ethnic Albanian minority and its Macedonian majority in the first place by recognising Kosovo.

"Why should Macedonia be threatened by such a [land-swap] solution? The Skopje government created this threat itself by breaking the law and recognising Kosovo's unilaterally declared independence. What if the Albanian-populated areas of Macedonia now declare independence? I hope not," he added.

Dacic spoke to FAZ on the same day that Serbia rejected an EU-brokered plan on better relations with Kosovo.

His government said in a statement on its website that it cannot agree for north Kosovo to be subject to Pristina's authority, because this would "not guarantee the full safety, survival and the protection of human rights of the Serbs" in the area.

It is unclear if the land-swap idea ever came up in the EU-mediated negotiations, which began in mid-2011.

In the final phase of the talks, Serbia instead proposed that north Kosovo Serbs should be ruled by an autonomous Association of Municipalities which controls its own police and courts - a solution which was also rejected by the US and by Kosovo itself.

The Serbian statement added that it wants to continue the EU-mediated dialogue despite the fact it ended formally last week after a 13-hour-long meeting in Brussels which saw heated tempers and raised voices.

If there is no Kosovo-Serbia deal by 16 April, the due date for a European Commission report on EU-Serbia relations, the commission is unlikely to recommend that EU countries open accession talks with Serbia this year.

For her part, EU foreign relations chief Catherine Ashton said on Monday she "regrets" Serbia's decision.

But she indicated she is happy for the dialogue to continue beyond its formal mandate.

"I believe that all the elements for an agreement on northern Kosovo are on the table … I hope that Kosovo and Serbia will not miss the opportunity to put the past behind them," she said.

Dacic, in the FAZ interview, also complained that Germany is being too tough by telling it to give up north Kosovo if it wants to make progress on EU accession.

"Germany is imposing unnecessary conditions in addition to those that have already been placed. It is time to finally move on and form strategic partnerships … Unfortunately, Germany and one or two of its neighbours in the EU are taking a very hard line against Serbia," he said.

"There is a misconception that you can solve all the problems of the Balkans by constantly putting pressure on Serbia," he added.

In terms of EU-US co-operation on former Yugoslavia, the EU is playing the lead role in rebuilding the region by offering countries the chance to join the Union in return for reforms.

But the US, which led the bombing campaign against Serbia in the Balkan wars, still holds huge sway.

The former US ambassador in Pristina, Christopher Dell, who left his post last summer, was known locally as the "King of Kosovo" in reference to his alleged influence over Thaci's government.

Senior US diplomats, such as Philip Reeker, who runs the Balkans bureau in the state department, regularly visit Brussels and speak with Thaci on the eve of his Ashton-Dacic meetings, in what the US mission to the EU calls "part of our ongoing support for this process."