An author of books on the Bulgarian mafia was shot dead on Monday, a day after the chief of an energy firm that repairs Bulgaria's nuclear power plant had been killed.
"Unfortunately these shootings have continued to take place on regular basis over the last couple of years and without successful prosecution," European Commission spokesman Mark Gray told a daily news briefing.
"Urgent action is required in the area of fighting organised crime in Bulgaria."
Bulgaria joined the EU in 2007 along with neighbouring Romania in the second wave of the bloc's eastward expansion, despite complaints by some European politicians it was not doing enough to combat organised crime and corruption.
Bulgarian Prime Minister Segrei Stanishev said in a statement on Tuesday the country would do its utmost to prosecute those responsible for the latest attacks.
"The government will continue the fight against organised crime with tough and focused actions. It has resolute political will to mobilise ... the state institutions in the fight against graft and organised crime," Stanishev said.
The Socialist-led government has been under growing pressure from the EU and at home to stop procrastinating and get serious about fighting rampant crime and graft.
The Commission will publish a report in mid-2008 on Bulgaria's progress in fighting graft and organised crime, in which it may propose sanctions if it deems the country's actions as insufficient.
Under the accession treaty, EU states may refuse automatic recognition, and enforcement, of civil and criminal judgments and arrest warrants issued by Romania or Bulgaria.
There have been more than 150 gangland assassinations since 2001. But despite its campaign against crime and graft, Bulgaria has failed to convict a single suspect, nor has it charged any senior officials with graft.
Georgi Stoev, 35, author of a series of books on the emergence of Bulgaria's underworld after communism collapsed in 1989, was shot once in the head in front of a hotel in central Sofia. He died of his wounds on Monday night.
On Sunday, police found Borislav Georgiev, manager of Atomenergoremont, shot twice in the head in the entrance of his apartment block.
Last Mod: 08 Nisan 2008, 15:08