Thousands march in Madrid supporting separatists on trial

Catalan pro-independence demonstrators hold "estelada," or separatist flags, as they arrive to Madrid, Spain, Saturday, March 16, 2019. Demonstrators

Catalan pro-independence demonstrators hold "estelada," or separatist flags, as they arrive to Madrid, Spain, Saturday, March 16, 2019. Demonstrators

A Catalan pro-independence demonstrator drinks using a wineskin, as they arrive to Madrid, Spain, Saturday, March 16, 2019. Tens of thousands are marc

A Catalan pro-independence demonstrator drinks using a wineskin, as they arrive to Madrid, Spain, Saturday, March 16, 2019. Tens of thousands are marc

Protesters hold a Spanish flag as Catalan pro-independence demonstrators wave "esteladas," or separatist flags as they arrive to Madrid, Spain, Saturd

Protesters hold a Spanish flag as Catalan pro-independence demonstrators wave "esteladas," or separatist flags as they arrive to Madrid, Spain, Saturd

Catalan pro-independence demonstrators hold "esteladas," or separatist flags, as they arrive to Madrid, Spain, Saturday, March 16, 2019. Tens of thous

Catalan pro-independence demonstrators hold "esteladas," or separatist flags, as they arrive to Madrid, Spain, Saturday, March 16, 2019. Tens of thous

MADRID (AP) — Tens of thousands are marching in Madrid to support Catalan politicians and activists standing trial for their attempt to secede from Spain.

The nine defendants face decades in prison on rebellion and other charges for staging a banned referendum in October 2017 and declaring Catalan independence, although they took no action to implement that.

Many supporters believe the defendants are "political prisoners."

Large pro-independence protests have been staged in Spain's northeastern region and in some European cities, but Saturday's is the first major separatist march in the Spanish capital.

Organizers expect 50,000 protesters, most of them traveling from Catalonia in some 500 buses.

A banner reading "self-determination is not a crime" opened the march.

Authorities in Madrid have deployed more than 500 police officers including riot police.