The visit of Bulgarian tax investigators to several posh upmarket districts around Sofia in helicopters last week has been described by the prime minister as "a snapshot" of the country's transition from communism to market economy.

"The sights that we saw from the helicopter paint a picture of the transition and what happened in Bulgaria over the last twenty years," Boyko Borisov said on Sunday.

His comment was in response to criticism by Socialist President Georgi Parvanov, who called the tax authorities raids "PR campaigns" and called on the government to "reveal who earned what during the transition period."

"The National Revenues Agency deserves to be congratulated for its courage because no one dared to enter these properties over the last twenty years," Borisov said.

In his words the ruling party GERB has the strength to take this step because "it is the only party, which has not taken advantage of its powers".

Bulgarian tax investigators visited several posh upmarket districts around Sofia in helicopters last week to see if the value of the luxury real estate, palaces around the capital of the poorest EU country, tallied with the owners' official revenues.

Opponents however have expressed doubts that an inventory of luxury real estate will generate huge tax revenues.