US President Barack Obama is going to nominate John Brennan as CIA Director, according to White House officials.

The Bulgarian Dnevnik online news agency informs that Obama is going to make the announcement Monday.

If confirmed, Brennan will replace General David Petraeus, who resigned last year after admitting to an extramarital affair.

Also on Monday, Chuck Hagel is expected to be nominated by the US President as Defense Secretary. Hagel will be replacing Leon Panetta.

Both appointments must be confirmed by the Senate.

Brennan, a veteran with a career span of 25 years with the Central Intelligence Agency, is currently Obama's Chief Counterterrorism Adviser. He is largely credited with the planning of the 2011 raid that killed Osama bin Laden.

Brennan was Obama's first choice for CIA Director and was to be nominated as early as 2008, but withdrew his name amid questions about his connection to interrogation techniques used during the administration of George W Bush. He denies having anything to do with the alleged torture of detainees at Guantanamo and even voiced strong opposition to them on several occasions.

Brennan visited Bulgaria shortly after the July 2012 terror act when 5 Israeli tourists and their Bulgarian bus driver were killed in an apparent suicide bombing at the Sarafovo airport in the Black Sea City of Burgas. He met in December with Bulgaria's Interior Minister, Tsvetan Tsvetanov, during the latter's trip to Washington DC.