The launch of the car service Uber in Buenos Aires led to traffic chaos in the Brazilian city on Friday when hundreds of taxis blocked streets in protest against it, dpa reported. Uber responded by offering all customers up to 15 trips valued at the equivalent of about 13.50 dollars for free. The company announced the offer on Twitter. The district attorney's office ordered a search of two suspected Uber offices in Buenos Aires over tax evasion suspicion and operating an illegal public transport, said prosecutor Martin Lapadu, the news agency Telam reported. Juan Jose Mendez, transport secretary for the municipal government, said that the car-sharing service was illegal, and Uber drivers could have their drivers' licences revoked for up to two years. An Uber spokesman defended the right of two people to arrange a private service. The city of Buenos Aires has 48,000 licensed taxis.