European Union hopeful Bulgaria wraps up more than four years of intensive negotiations Tuesday, and if it implements substantial reforms demanded by Brussels the eastern European country will become the newest member of the bloc in 2007.

Three years ago, Bulgaria -- along with Romania -- was considered a straggler for EU membership when the union invited 10 mostly eastern European countries to join last May 1.

Since then, the formerly communist country has undertaken major political and economic reforms, and unless talks hit a last minute snag, negotiations will conclude in Luxembourg Tuesday, an EU source said.

EU Enlargement Commissioner Guenter Verheugen has said the commission will keep a watchful eye on how Bulgaria carries out promised reforms, notably putting into practice a "monitoring system" to oversee its fight against corruption and organized crime.

Verheugen, who was recently in Sofia to spur the reform-minded government along, said such monitoring could continue until 2006 "if there is a need to do so".

The system is not new -- it was previously used for the 10 EU candidates which joined the pan-Europe bloc on May 1.

"You can't ask that a country put everything into place from the moment the negotiations end," an EU diplomat said. He stressed however that Bulgaria had to continue its efforts to prove it was worthy of membership.

The government in Sofia is happy to take on the challenge, saying it still has plenty of time for the necessary reforms.

"We have two and a half years before (January 1, 2007), which is long enough to allow us to be prepared in the best possible way," Foreign Minister Solomon Passy said.

If the commission wanted to monitor the situation, they were "welcome," he added.

Aside from corruption and crime, energy has been a major issue in Bulgaria's EU accession talks, which Passy said had been a "bitter experience" during the negotiations.

Sofia has committed itself to shutting down by 2006 two nuclear reactors in Kozloduy in the north of the country, plants which provide nearly half of the country's electricity needs.

Brussels has demanded the plants be closed citing safety concerns, but the plan has run into virulent popular opposition at home. Last week, 78 lawmakers called for a referendum to determine whether the plants should remain open.

Verheugen has however ruled out reopening the energy chapter just before the end of its talks, which he said neither Sofia of the 25 members of the EU wanted to do.

As the EU extends its reach into eastern Europe, Bulgaria is already looking much further the new frontiers if Sofia and Bucharest join in 2007.

Passi said he hoped the EU would consider giving neighboring Central Asian and Caucasus countries "propsects" for joining, without which those nations "may be tempted or forced to join another family".

"Who would have thought in 1990 that Bulgaria would become a member of NATO and the EU? Very few people. But I am convinced that in 15 years time we will be examining very seriously the accession of" Armenia, Azerbaijan and Georgia, he said.

"I know the border one day will move eastward. Everything is moving eastward. NATO is moving eastward, the EU is moving eastward."