Thousands of people rallied in a rainstorm in Barcelona on Tuesday vowing to defy Spain's move to block a referendum on independence for their Catalonia region.

Waving Catalan independence flags of red and yellow stripes overlaid with a white star on a blue background, demonstrators crowded on Sant Jaume square in the northeastern city under umbrellas, yelling "We will vote."

Spain's Prime Minister Mariano Rajoy said Tuesday he was open to proposals on reforming the country's constitution as demanded by rivals in response to the Catalonia region's demands for independence, but warned they were not his "priority."

A day after filing an appeal at Spain's Constitutional Court to block Catalan leaders from holding a referendum on independence for their region, Rajoy challenged the opposition Socialists to present a detailed plan for reform.

Catalan leaders launched a legal battle Tuesday to get their drive for a referendum on independence from Spain back on track after a court suspended it.

Angry separatists in the region planned protests after Spain's Constitutional Court halted the plan to hold the vote on November 9.

Spain's Constitutional Court on Monday suspended an independence referendum called by Catalonia for November 9, although leaders of the rich northeastern region vowed to press ahead anyway with preparations for the vote.

The unanimous and expected decision by the court's 12 judges came just hours after Spain's central government asked it to declare the independence referendum illegal on the grounds that it breaches the country's constitution.

Here are key dates in the campaign for the Catalonia region to gain independence from the rest of Spain:

October 25, 1979: During Spain's transition to democracy after the death in 1975 of the dictator Francisco Franco, Catalans approve in a referendum a charter defining Catalonia as an autonomous community under Spain's constitution.

Catalonia's president on Saturday formally called a referendum to decide whether Spain's richest region should be independent, in a defiant move immediately rejected by Madrid as anti-constitutional.

Shortly after Artur Mas set the vote for November 9, the Spanish government said the referendum would not be allowed to take place, with Deputy Prime Minister Soraya Saenz de Santamaria warning no one "was above the national will of the Spanish people."

Catalonia's president said he will on Saturday formally call a vote for November 9 on whether the region should be independent from Spain, defying Madrid's vows to block the move.

"On Saturday I will sign the decree to call the vote, just as I promised," Catalonia's President Artur Mas was quoted as saying in a statement released by his regional government.

Spain and Morocco on Friday arrested nine suspected members of a group in north Africa linked to the violent Islamic State jihadists, the Spanish government said.

Spanish police and Moroccan security forces "today detained nine members of a terrorist cell... linked to the terrorist organization Islamic State", Spain's interior ministry said.

Three more people have died from Legionnaire's disease in Catalonia in northeastern Spain, officials said Tuesday, bringing to seven the death toll from the lung infection in the region in just over a week.

The three deaths took place in Ripollet, a town near Barcelona, Catalonia's health department said.

Catalonia's regional parliament on Friday passed a law that its leaders say will authorize them to hold a non-binding "consultation" on independence from Spain on November 9.

The law was passed with 106 votes in favor and 28 against.