The head of Bulgaria's national security agency, who resigned on Wednesday amid accusations about his office's performance, may be soon appointed security adviser of the prime minister.

"The former director of the Bulgarian State Agency for National Security (DANS) Tsvetlin Yovchev is very likely to replace Rumen Milanov, Borisov's security adviser," Standard daily reported on Friday.

A day earlier Rumen Milanov was appointed head of the newly established Center for Prevention of Organized Crime and Corruption (BORKOR), which the center-right government set up to clear Bulgaria's image as one of the most corrupt EU members.

Yovchev submitted his resignation on Wednesday, asking Prime Minister Boyko Borisov that he be dismissed from office before the end of his term.

The decision has been prompted by the government's consistent lack of trust in his skills, Yovchev said in his motives.

According to Yovchev he has failed to meet the prime minister's expectations as there was a clash over what the agency's priorities should be.

The news comes just days after a bomb exploded in front of the offices of Galeria, an anti-government newspaper, in downtown Sofia.

Right after the blast occurred last Thursday Prime Minister Boyko Borisov instructed Interior Minister Tsvetan Tsvetanov and DANS head Tsvetlin Yovchev to take urgent measures and arrest the masterminder. He pointed out his assessment of the work of the two top cops will depend on their performance with respect to the Galeria explosion.

Last month Galeria published transcripts of taped phone conversations between senior government officials and Customs Office chief Vanyo Tanov, which prompted Prime Minister Boyko Borisov to seek and win a confidence vote in Parliament on Jan. 20.

The tapes, whose authenticity is still not verified, allege that the government of PM Boyko Borisov is favoring certain companies and individuals with respect to investigations and appointments in the Customs Agency.

Yovchev was appointed Director of DANS after the prime minister accepted the resignation of the former head Petko Sertov at the beginning of August 2009. He took office on August 10 after President Georgi Parvanov issued a decree for his appointment.

When DANS was created in January 2008, Yovchev became the head of the Counter-Intelligence Directorate. He resigned in October 2008, citing personal reasons.