Thousands of people are attending rival demonstrations - one in Barcelona and the other in Madrid - amid tensions over Catalonia's independence referendum.
People in the capital Madrid waved red and yellow Spanish flags in support of unity, while those in Barcelona, the Catalan regional capital, dressed in white to symbolise their desire for talks and a peaceful resolution to the crisis.
Some people in Madrid also wore white in support of dialogue.
At the regional government's headquarters in Barcelona's Sant Juane Square, demonstrators chanted "We want to talk!" and carried signs saying "More Negotiation, Less Testosterone!" and "Talk or Resign!"
In Madrid, people gathered at the Cibeles fountain carrying a huge banner demanding leaders start talking. Some chanted "Less hate, and more understanding!"
But the pro-dialogue rally nearly clashed with a large pro-unity demonstration in Plaza de Colon where thousands of people carried Spanish flags and some danced around a fountain, before police separated the two groups.
Separatists claimed an overwhelming victory in last Sunday's referendum, plunging the country into a political crisis. The vote was declared illegal, invalid and unconstitutional by Madrid.
Ahead of Saturday's protests, a leading Catalan politician called for a "ceasefire" with Spain to lower tensions created by the region's push for independence.
Santi Vila, the regional government's business minister, told Cadena SER Radio it may be the "last chance" for "a new opportunity for dialogue" with Spanish authorities.
"We have to give it one more chance, maybe the last chance, and perhaps the only way that can happen is to start with a ceasefire," Mr Vila said.
"We can all calm down and give ourselves the opportunity to not take any decisions and see what channels we can open up to start a serene dialogue."
Meanwhile, Spain's secretary of state for foreign affairs has told Sky News a violent police crackdown against Catalan voters during the referendum was "absolutely proportionate" .
Ildefonso Castro also urged Catalan leaders not to declare independence, saying Catalan ministers will become "outlaws" if they do.
He said: "The most important thing is to be within the frame of the Spanish constitution. You can disagree with the law, but you cannot disobey the law. If you disobey the law, you become an outlaw."
Less than half the electorate voted in the referendum, and the most recent regional elections and opinion polls suggest Catalans are split roughly in half over independence.
Amid the tensions, some banks and businesses declared they were relocating so regional secession would not cause them to drop out of the European Union and the single market.
Mr Vila said he is against an immediate unilateral declaration of Catalan independence, but wants the Madrid government to hand back powers recently taken from the regional administration and a committee of experts from both sides formed to work out a solution to the crisis.