Mass checks of illicit transport of passengers are to begin in Sofia, the Transport Ministry said. The so-called Uber cabs that have an increasing number of customers will be inspected too. They have come under strong criticism for allegedly illegal transportation of passengers. A few months after they appeared on the market in Bulgaria Uber cabs have already faced with vocal opposition. According to taxi companies Uber are 100% illegal: they do not hold licenses for transportation of passengers and special driver licenses, do not use fiscal devices and are not branded.