The president of Spain's Catalonia region has called for an immediate halt to violence, as protests continued for the third night."We condemn violence... This has to stop right now," Quim Torra said.On Wednesday, protesters set up burning barricades and hurled projectiles at police in Barcelona, the capital of the autonomous region in the north-east.Monday's sentencing of nine separatist leaders triggered protests in support of Catalonia's independence.Protesters have reportedly been using an app known as Tsunami Democratic, which directs them to protest sites in Catalan cities.The Spanish authorities say they are investigating who is co-ordinating the disruption.

What did the Catalan president say?

In a televised statement, Mr Torra said: "We will not permit incidents like those we are seeing in the streets."This has to stop right now. There is no reason nor justification for burning cars, nor any other vandalism." On Wednesday, protesters hurled projectiles at riot police in BarcelonaMr Torra, who advocates independence for Catalonia, was speaking after Spanish Prime Minister Pedro Sánchez had made a direct appeal to him to condemn the violence.Pro-independence leaders - who control the Catalan regional government - said earlier they would keep pushing for a new referendum on secession from Spain.

Why are people protesting?

The protests began after nine Catalan independence leaders were handed jail sentences of between nine and 13 years by Spain's Supreme Court on Monday. Riot police in Barcelona tried to disperse protesters who set up burning barricadesThe separatists were convicted of sedition over their role in an independence referendum in 2017, which Spain said was illegal.Another three were found guilty of disobedience and fined, but not jailed. All 12 defendants denied the charges.On Monday, thousands of protesters blocked roads to Barcelona's El Prat airport - a major transport hub. Clashes broke out on Monday as protesters blocked road access to Barcelona's El Prat airportMore than 100 flights were cancelled as demonstrators fought running battles with riot police at the terminal buildings.

What is behind the Catalonia unrest?

Catalan nationalists have long complained that their region, which has a distinct history dating back almost 1,000 years, sends too much money to poorer parts of Spain, through taxes which are controlled by Madrid.The wealthy region is home to about 7.5 million people, with their own language, parliament, flag and anthem.In September, a march in Barcelona in support of Catalonia's independence from Spain drew crowds of about 600,000 people - one of the lowest turnouts in the eight-year history of the annual rally.