SOFIA, Aug. 25 (Xinhua) -- Bulgarian authorities have busted a network of four illegal cigarette factories and arrested 19 suspects, the country's Ministry of Interior said in a statement here on Saturday.

More than 42 tons of illegal tobacco worth 4.12 million U.S. dollars and 190,000 cigarette packs of different brands worth 890,000 dollars were found on Friday in the facilities, which were located in the towns of Dupnitsa, Gorna Oryahovitsa and Tutrakan, the statement said.

Authorities have also confiscated machinery and equipment for the production of cigarettes as well as 11 trucks and more than 10 cars, it said.

The investigation found that each of the four illegal factories produced an average of about 100,000 cigarette packs per day, the statement said.

Revenue from tobacco products is of great importance for Bulgaria's state budget. Its share in total tax revenue is 9 to 10 percent per year.