Some 800,000 people took part in the Barcelona rally on Sunday, according to police, many of them wearing white T-shirts bearing the word "Ready."

Participants - many draped in blue, red and yellow pro-independence banners - gathered in the city's Ciutadella park ahead of the demonstration, holding aloft yellow cardboard signs to simulate a beating heart.

The event was held on Catalonia's national day, the "Diada," which marks the 1714 conquest of Barcelona by Spain's King Felipe V after a siege that lasted more than a year.

Secessionist parties won a clear majority in Catalonia's regional parliament for the first time ever last year, and approved a plan to achieve independence in mid-2017. However, the plan ran into trouble in June when the winning coalition government lost the support of the small anti-capitalist CUP party, which has a hard line on independence.

Time running out?

Pro-independence supporters said they hoped the mass protest would reinvigorate the process of secession.

"This is the moment to stand united for the 'yes' to the Catalan Republic," said Jordi Sanchez, head of the pro-independence Catalan National Assembly organization. "We are impatient," he added.

The head of Catalonia's regional government, Carles Puigdemont, told a meeting of foreign journalists ahead of the rally that "critical decisions" were to be taken in the months to come.

All across the region

In addition to the rally in Barcelona, demonstrations were held in the cities of Tarragona in the south, Berga in central Catalonia, Salt in the north and Lleida in the east.

For years, separatists have tried in vain to gain approval from Spain's central government to hold an independence referendum similar to the one held in 2014 in Scotland, which resulted in a "no" vote to independence from Britain. However, the central government in Madrid, led by conservative acting Prime Minister Mariano Rajoy, remains steadfastly opposed to the idea.

The separatist movement burst into life in 2012, amid deep economic crisis and the intensifying stand-off with Madrid.

rc/gsw (AP, AFP)