The official, speaking on condition of anonymity, said a special EU task force would meet on October 2 to discuss a report from chief UN prosecutor Carla del Ponte on Zagreb's efforts to track down fugitive war crimes suspect Ante Gotovina.
If the group, headed by British Foreign Secretary Jack Straw, concluded that Croatia was now cooperating fully with the International Criminal Tribunal for the former Yugoslavia, EU foreign ministers meeting on October 3 in Luxembourg might decide to open talks immediately, the official told Reuters.
The news agency recalled that Del Ponte this week accused the Roman Catholic church of sheltering Gotovina in a Franciscan monastery. She has said she is awaiting one more unspecified action by Croatia to prove its good faith, even if the fugitive has not yet been captured.
Del Ponte will visit the region on September 29 and 30, after which she will submit a new report to the EU.
EU diplomats said Croatia had asked the EU to hold off the task force review, initially planned for mid-September, until after her visit to Zagreb, leaving little time for a decision on whether to open talks at the same time as with Turkey.
"It is theoretically still possible to decide on October 3 but the timetable is very tight and it depends on full Croatian cooperation," the European official said.