Thousands of Portuguese cab drivers blocked access to Lisbon international airport on Monday and plan to move strike action to Faro next week.
The protest is against government plans to allow the modern, smart-phone based transport companies, such as Uber and Cabify, into the market with rules due to be formalised later this year.
Travellers arriving at Lisbon airport queued for hours to buy a metro ticket to the city centre while angry taxi drivers attacked and damaged cars.
The protesters scrapped with riot police who then sued tear gas and fired blanks in an attempt to restore order.
The unrest was subdued when representatives of the drivers' unions got their wish and were summoned for discussions with Environment Minister, João Pedro Fernandes who is unlikely to be able to handle this level of anger and complaint.
Carlos Ramos, the head of the Portuguese Taxi Federation, said after the meeting that Fernandes has given them "a fistful of nothing" and that the protesters would stay on at the airport, which they did until 02:30 on Tuesday morning.
The minister reckoned the meeting had been “productive” but admitted that "deep divergences remained" over taxi drivers' demands to limit the number of cars operating in the alternative transport service field.
In June this year, a Lisbon court overturned a previous ban on Uber operating in Portugal with the Prime Minister saying he wants to regulate the new app-based services by introducing training for drivers and making them pay insurance for their passengers.
The president of taxi association ANTRAL, Florencio Almeida, said more action will be organised for next week outside the council building in Faro and in Oporto as well as in Lisbon.
Speaking at the end of the protest, Florencio Almeida said the action had been "very positive" and he now aims to involve the President of the Republic, Marcelo Rebelo de Sousa.
There were three arrests for damage to property with one man found to be carrying a gun.
