During an official visit to Bucharest, he also appealed to the European Union to do its best to prevent Belgrade’s isolation.
“It would be a very bad development if Serbia sinks down into isolation,” Bildt told a joint press conference with his Romanian counterpart Adrian Cioroianu.
“We should at least try to do whatever we can do to prevent that from happening with Serbia, in a dialogue both concerning its own European perspective, but also concerning how we should manage the disagreement that is there over Kosovo,” he added.
Bildt noted that the EU had offered Serbia a cooperation deal in late January paving the way for its entry into the bloc and said he hoped Belgrade would sign it.
“We are open to suggestions from Belgrade on other items that could be in that agreement. But so far at the moment, I would say, it has not been taken up, which I regret,” he said.
“I can understand it to a certain extent now, but I hope it can be taken up very shortly.”
Meanwhile, Cioroianu welcomed the fact that EU members had reached a consensus on two key issues related to Kosovo: deploying a European police and justice mission to the province and allowing individual member states to decide whether or not to recognize it.
Sweden has said it will recognize Kosovo’s independence, along with the United States and most EU member states, but Romania has said it will not.