Negotiations to seal Bulgaria's 2007 entry into the European Union could be concluded by the middle of the year, German Chancellor Gerhard Schroeder said Thursday.

After talks here with visiting Bulgarian counterpart Simeon Saxe-Coburg, Schroeder said he was confident Bulgaria would achieve its target of joining the bloc in four years' time.

The chancellor said Sofia had made "such strong progress" that there was "a very, very big chance" that the negotiations could be concluded by the end of the Irish EU presidency on June 30.

"A country that has made as much progress as Bulgaria has should not suffer delays," he told a joint press conference.

Romania is also eyeing a 2007 entry date, but Schroeder indicated that it had further to go to satisfy membership criteria.

"The difficulties that still exist must be overcome," he said, pledging the support of Germany to do so.

Romania has made heavy weather of tackling corruption and implementing the necessary structural adjustments to its economy, and it will have to speed up reforms if it hopes to join in 2007, EU officials say.

Saxe-Coburg appealed for greater German investment in Bulgaria, a call joined by Schroeder who said their volume of bilateral trade last year exceeded two billion euros (2.4 billion dollars) for the first time.