But the former Kosovar guerrilla chief cancelled the trip when Serbia said he’d be arrested on the basis of an old warrant.

The warrant stems from his conviction, in absentia, for “terrorism” in 1997 when the late Serb dictator, Slobodan Milosevic, was in power.

Thaci was already arrested once, in Hungary in 2003, after Serbia red-flagged him in the database of Interpol, the international police body. But Hungary released him following a brief detention.

The new dispute comes amid EU-led attempts to “normalise” relations between the two sides.

EU powers, such as Germany and the UK, have linked Serbia’s compliance with the process to the EU’s opening of first chapters in accession talks later this year.

For Thaci, the NGO row shows that Serbia isn’t acting in good faith.

“My participation was hindered by lack of political will”, he told EUobserver on Tuesday (21 April).

“It’s regrettable that Serbia has lost the opportunity to overcome the barriers of the past and to focus on the future of good neighbourly relations and a European approach”, he added.

“This proves there’s still much work to be done to complete the normalisation of relations”.

Kosovar sources also noted that the Serb foreign minister, Ivica Dacic, and PM, Aleksandar Vucic, have been to Pristina despite their controversial past in the Milosevic regime.

But for Serbia, the Thaci incident is a provocation organised by Pristina and by Russia-hostile EU states.

A Serb diplomat told EUobserver that Thaci violated protocol by failing to notify Belgrade of his travel plans.

“It really wasn’t discussed with the Serb government the way it should've been”, he said.

He noted the NGO, the Youth Education Committee, is co-financed by the British government - a leading critic of Serbia’s close ties with Russia in the context of the Ukraine conflict.

Serbia, under the terms of its Stabilisation and Association Agreement with the EU, is obliged to align itself with EU foreign policy.

But it hasn’t imposed EU-model sanctions on Russia and its president is to attend a WWII victory parade in May in Moscow with a detachment of 70-or-so Serb soldiers.

“We share the same anti-fascist tradition with Russia and we openly proclaim we want nothing to do with the EU sanctions”, the Serb diplomat added.

“So we think this is a bit of pressure [by the UK and like-minded EU states] to fall into line by creating a pretext not to open accession chapters ... We should be given some slack because there haven’t been any provocations [against Kosovo] from the Serb side”.

Tusk

In what appears to corroborate the theory, EU Council president Donald Tusk voiced annoyance with Serbia after meeting Vucic in Brussels on Tuesday.

“I underlined the importance of Serbia's foreign policy approach being guided by its number one strategic objective: to join the European Union”, Tusk said.

“I expressed the EU's expectation that Serbia progressively aligns with the European Union's positions in the process up to accession”.

But the “normalisation” process is moving forward.

Normal?

An expert-level meeting last week discussed border control issues, privatisation, and local rule by Kosovar Serbs, while Vucic is to meet Kosovo’s PM, Isa Mustafa, later this month.

Meanwhile, the NGO dispute might help Thaci to avoid Hungary-type arrest incidents when he loses his immunity as a minister in future.

But it won’t help him if he is indicted, as is widely expected, on charges of organ trafficking by a special EU tribunal being set up in The Hague.