Thousands demonstrated in the region on Thursday
|
Basque nationalist politicians are urging supporters to attend rallies on Friday in solidarity with victims of Thursday's bomb attacks in Madrid.
At lunchtime, people in the Basque region stopped work for 15 minutes to honour the victims' memory.
Basque regional prime minister Juan Jose Ibarretxe has condemned the attacks, which he said had nothing to do with the Basque people.
But evidence so far suggests that Basque separatists Eta may be involved.
Mr Ibarretxe warned against rushing to blame the group.
"There is reasonable doubt as to who carried out this outrage," he said.
"The government initially attributed the attack to Eta in good faith. After that there was some confusion."
But Basque justice minister Joseba Azkarraga said he was "convinced" Eta was not behind the attack.
In an interview for Basque TV, he said that if Eta was not responsible it should issue a clear statement to this effect.
He also accused the Spanish government of "prevarication" and attributing blame to an organisation "not shown to be responsible".
Scepticism
Hundreds came onto the streets in the regional capital, Vitoria, at 1200 local time (1100 GMT) to pay their respects.
Large demonstrations are planned there for the evening, as well as in the cities of Bilbao and San Sebastian.
Senior officials are expected to attend, including the French and Spanish justice ministers.
On Thursday night, thousands gathered in cities in the Basque region to express their outrage.
The BBC's Tristana Moore in Vitoria says there is a real feeling of shock in the region, with many wearing black ribbons as a mark of respect for the victims.
But people are also very sceptical, our correspondent says, with many saying there was no way Eta could have been responsible for the bombing.
While campaigning for Sunday's general election has been suspended, police remain on high alert across the region.