(Adds EU enlargement commissioner)
BRDO, Slovenia, Feb 22 European Union officials called on Serbia on Friday to do more to protect foreign embassies targeted in protests against Kosovo's secession, warning the violence could have an impact on EU-Serbian ties.
EU foreign policy chief Javier Solana told reporters at an EU event in Slovenia that the violence could harm progress on a preliminary deal on ties with the European Union, the Stabilisation and Association Agreement (SAA).
"Things will have to calm down before we can recuperate the climate that would allow for any contact to move on the SAA," Solana said after the storming of the U.S. embassy in Belgrade and attacks on the German and British missions on Thursday.
EU Enlargement Commissioner Olli Rehn said the European Union respected the democratic right of the Serbian people to voice their opinion on developments in Kosovo, "but the use of violence for expressing one's opinion is unacceptable", he said.
"I call on the Serbian authorities to ensure the proper protection of diplomatic missions in the country," Rehn said in a statement.
The Stabilisation and Association Agreement was initialled last year but the EU has said it will not sign it until Belgrade fully cooperates with the U.N. war crimes tribunal for the former Yugoslavia.
The EU was ready to sign an interim trade deal but Belgrade's nationalist prime minister Vojislav Kostunica blocked the move earlier this month because of the row over Kosovo.
Serbian rioters enraged by Kosovo's secession stormed the U.S. embassy in Belgrade on Thursday and set it on fire, leaving one protester dead. Germany and Britain also said their missions had been vandalised.
"I only wish the Serbian police had intervened more quickly," said German Defence Minister Franz Josef Jung, echoing U.S. complaints of a lack of protection for foreign missions.
Solana praised a statement by Serbia's pro-European President Boris Tadic trying to calm the situation but said the authorities' response as a whole had been insufficient.
"I don't think that in other places the behaviour of the authorities was of the same manner (as Tadic's)," he said.
Some 200,000 people attended the state-backed rally and officials said police were overwhelmed by the biggest march since protesters stormed the old Yugoslav parliament building in 2000 to oust nationalist leader Slobodan Milosevic.
But police were nowhere to be seen when just a few score rioters -- many wearing balaclavas -- attacked the U.S. embassy for the second time in a week. (Reporting by Mark John; Writing by Ingrid Melander; Editing by David Brunnstrom)