Prime Minister Pedro Sanchez has said the Spanish cabinet will approve pardons for nine separatist Catalan politicians and activists imprisoned for their roles in the 2017 push to break away from Spain.

Mr Sanchez made the announcement in Barcelona during a speech set to lay the road map for the future of the north-eastern region before a few hundred civil society representatives. He said the cabinet would approve the pardons on Tuesday.

Twelve separatist leaders were convicted for sedition and other crimes and nine of them were handed lengthy prison terms after they pushed ahead with a banned secession referendum and declared independence a few days later based on its results. Most unionists boycotted the vote, which took place amid police violence to stop it.

No prominent pro-independence supporters attended Mr Sanchez's speech at the Catalan regional capital's opera house. Outside the venue, an anti-establishment party and the main pro-independence civil society group were holding a protest.

"With this action, we materially get nine people out of prison, but we symbolically add millions and millions of people to coexistence," Mr Sanchez said in his speech, titled Reunion: a project for the future of all Spain."

"We are going to do it for the sake of agreement, we are going to do it wholeheartedly," he added.

The prime minister was interrupted by an activist who carried the unofficial pro-independence Catalan flag and shouted in favour of granting full amnesty to the separatists. While pardons are granted by the government as a way to spare punishment to those convicted, amnesty is seen as a recognition of no fault in the first place.

The pardons have become a divisive political issue.

Thousands opposed to the move called for Mr Sanchez's resignation earlier this month during a protest in Madrid, supported by the three Spanish opposition parties, from the political centre to the far-right.