Serbia's chief negotiator on Tuesday called on the European Union to continue accession talks in June as planned, criticising the opposition from Balkans neighbour Croatia.
"Technically speaking, yes, they (Croatia) are blocking... they are stopping the possibility to go further," Tanja Miscevic told AFP.
"I am not going to call it a blockade because they never formally vetoed something.... But they are doing something else, they are not giving the so-called 'green light' on those documents," she said.
Croatia is opposed to opening negotiations on several key chapters -- the judicial system, fundamental rights and security. Talks with a candidate country on any chapter need the approval of all 28 EU member states.
The hurdles, according to Zagreb, include Belgrade's cooperation with The Hague-based UN war crimes tribunal for the former Yugoslavia (ICTY) and political representation of minorities.
Serbia and Croatia have had an uneasy relationship, particularly since the 1991-1995 war when Belgrade backed Croatian Serbs who were against declaring independence from Yugoslavia. The conflict claimed 20,000 lives and left hundreds of thousands of people homeless.
Croatia became the newest member of the EU in 2013. Serbia started accession talks in January 2014, but did not open the first chapters for negotiations before December last year.
Miscevic said Serbia has been working on reforms as required for EU membership, but that the country needs to know there "is light at the end of the tunnel, whenever the end of the tunnel is."
On April 24 Serbian Prime Minister Aleksandar Vucic won early elections that he said were called to get a clear mandate to press ahead with the EU reforms.
"I am a very dedicated Euro optimist... but I am also at the same time extremely frustrated," Miscevic said.
"It took us two years to open the first chapters for the negotiations," she noted.
Miscevic however added that she would not ask the European Commission to put pressure on Croatia.
"It is not up to us... It is up to 27 member states to tell the 28th member state that actually they are wrong," she said.
The EU has said there will be no further enlargement of the bloc until 2020.
