Hundreds of cab drivers brought traffic to a crawl Tuesday in Lisbon and other Portuguese cities as they held the latest in a string of protests worldwide against US-based taxi app Uber.

Recent months have seen a flurry of protests by drivers against the controversial smartphone-based ride service amid claims Uber provides unfair competition by flouting rules and restrictions regulating professional vehicles.

Uber launched in Lisbon a year ago but Antral -- one of Portugal's main drivers' associations -- earlier this year obtained a civil court ruling preventing the firm from operating nationwide.

The ruling was filed against Uber's US-based, rather than Europe-based, incarnation.

Antral said some 3,000 taxis joined Tuesday's go-slow demonstration in the capital -- police put the figure at 700.

Parallel protests in the northern city of Porto and Faro in the south drew the support of 800 and 150, Lusa news agency reported.

"No to illegal transport" and "For fair competition" were among slogans some drivers pasted onto their windscreens.

"Thanks to Uber, we are losing customers -- especially on airport runs. The authorities see what is going on -- but do nothing," complained Carlos Ferreira, a 66-year-old Lisbon cabbie.

- Sympathy and frustration -

Antral slammed Uber for "illegally" continuing to operate despite the court ruling.

Uber's head of services in Portugal, Rui Bento, said the firm had appealed the ruling and was awaiting a final decision.

The latest protests follow similarly vociferous complaints elsewhere in Europe, the United States and India.

Uber resumed its Indian operations in January after last year being banned following a rape allegation against one of its drivers.

June saw angry scenes in Paris, resulting in rioting by taxi drivers and the arrest of two Uber executives.

The company responded by suspending its lower cost UberPOP service in a country which has restricted its activities.

Unions representing taxis in Brussels have called a strike for September 16, with drivers from other European capitals also expected to participate.

Visitors to Lisbon were divided between sympathy and frustration.

"We understand the drivers. I prefer to pay a few euros more and reach my destination safely," said German Michael Zerwas, 50.

But Briton Sarah Chapman, 52, was angry.

"My father is in a coma in hospital in Lisbon. I wanted to pay him a last visit before heading back to the United Kingdom. But thanks to the taxi strike I shan't be able to see him."

Antral chairman Florencio Almeida insisted the action was justified.

"Uber are practising unfair competition with taxis and don't respect the law," said Almeida.

Source: AFP