* Parliament vote delayed, but chances of approval rise
* World Bank vice-president set to be Bulgaria's nominee
* Incident shows parliament's growing assertiveness
By Marcin Grajewski and Anna Mudeva
BRUSSELS/SOFIA, Jan 19 (Reuters) - Bulgarian Foreign Minister Rumiana Jeleva offered to resign on Tuesday and withdrew her candidacy for the European Commission, removing an obstacle that had threatened to derail the new EU executive.
Jeleva, 40, tendered her resignation in a letter to Prime Minister Boiko Borisov after some members of the European Parliament made clear they would not support her appointment because of concerns over her competence and business ties.
Although the EU legislature cannot block single candidates, it can reject the entire 27-member Commission, the body responsible for enforcing EU rules. This would have been a big blow to Commission President Jose Manuel Barroso.
Jeleva's withdrawal will delay the formation of the next Commission since parliament will now need time to organise hearings for her replacement. But it increases the likelihood that the Commission line-up will ultimately win approval.
Lawmakers said the vote to approve the Commission, originally scheduled for Jan. 26, would now be held on Feb. 9.
"I ask you to accept my resignation from all positions I hold so that you can do the necessary to withdraw my nomination as Bulgaria's European commissioner," Jeleva wrote in her letter to Borisov, published by Bulgaria's foreign ministry.
"I have no hope of getting an impartial and objective assessment (from parliament's development committee) and I am giving Mr Borisov the chance to propose ... a new candidate."
Borisov confirmed that he had withdrawn her nomination for the Brussels post but said he had rejected her resignation as foreign minister and wanted her to stay on.
Her withdrawal is a setback for the EU's poorest member state, which has faced strong pressure from Brussels to tackle corruption and organised crime since it joined the bloc in 2007. [nLDE60I1F2]
Pressure on Jeleva to withdraw grew almost immediately after her hearing for humanitarian aid commissioner last week. The Socialists and Greens said they had concerns about her qualifications and her business background in Bulgaria.
To replace Jeleva, Borisov has put forward Kristalina Georgieva, a senior World Bank official with a long track record in aid to the developing world who should be a strong candidate. [nLDE60I15K]
PARLIAMENT'S INCREASING ASSERTIVENESS
The centre-right European People's Party, which had strongly backed Jeleva's candidacy, expressed its regret at her withdrawal but did not immediately raise the stakes against its Socialist and Green opponents in parliament.
The EPP, the largest group in parliament, has concerns about some centre-left Commission candidates. Yet while it could seek revenge for Jeleva by trying to force out a leftist candidate, it has shown no intention of blocking any candidate outright.
The Commission, which consists of one representative from each EU member state, is appointed for five years and has important regulatory, legislative and policy-shaping powers in the bloc, a trading power with 500 million citizens.
Barroso, whose second term of office will now be delayed beyond its planned Feb. 1 start, had strongly backed Jeleva but risked being damaged politically had he persisted in defending her candidacy. It is the second time he has faced problems winning approval for his Commission nominees.
In 2004, Italy's Rocco Buttiglione, a Catholic conservative, had to be withdrawn as a candidate in Barroso's first Commission after he made comments about homosexuality being a sin.
Tuesday's events highlight the increasing assertiveness of the European Parliament, which has gained new powers under the Lisbon treaty. The treaty, which came into force last month, is meant to reform the bloc's institutions, improve decision-making and strengthen the European Union's role on the world stage.
The heads of parliamentary groups will meet in Strasbourg on Thursday to discuss the Commission candidates. That meeting may reveal whether there is likely to be further dispute over the line-up or whether it is now set for approval. (For SNAP ANALYSIS on Bulgarian's exit, click on [nLDE60I0Z8]) (For TAKE A LOOK on key EU news, click on [ID:nEU]) (Reporting by Luke Baker, Justyna Pawlak and Darren Ennis in Brussels and Anna Mudeva in Sofia; writing by Timothy Heritage and Luke Baker; editing by Tim Pearce)