A part of a historic building in Sofia where Bulgarian state-owned railway company BDZ Passenger Services is headquartered, has been put up for sale by a private enforcement agent for a starting price of 7.3 million levs ($4.4 million/3.7 million euro), local media reported on Monday.The private enforcement agent has put up for sale an area of 1,854 sq m, which represents half of the total area of the building, Capital business newspaper reported in its online edition.Last week, Capital said that bank accounts of BDZ Passenger Services have been temporarily blocked due to creditors' claims.On Thursday, Bulgarian transport minister Ivaylo Moskovski said he has asked the finance ministry to grant state aid to the company.(1 euro = 1.95583 levs)