About 170,000 people took to the streets a day after Prime Minister Pedro Sanchez was sworn in for a second term.

Tens of thousands of demonstrators have marched through Madrid to protest against a controversial Catalan amnesty law that allowed Spanish Prime Minister Pedro Sanchez to form a government for a second term.

Sánchez’s Spanish Socialist Workers’ Party (PSOE) secured supporting the Catalan separatist Junts party by offering amnesty to those linked to a botched attempt at regional independence six years ago.

Authorities said more than 170,000 people took part in the largest protest yet against the deal on Saturday, prompting opposition to take to the streets in cities across the country.

Sanchez was sworn in on Friday, nearly four months after a inconclusive election left the country with a parliament without a majority. The conservative People’s Party (PP), the largest opposition party, won the largest share of the vote, but the right-wing coalition with the far-right Vox party failed to achieve the absolute majority needed to form a government.

Protesters waved Spanish flags and held signs that read “Sanchez traitor” and “Don’t sell Spain.”

Four justice associations, opposition parties and business leaders say the law threatens the rule of law and the separation of powers.

Among the demonstrators were PP leader Alberto Nunez Feijoo and Vox leader Santiago Abascal.

After the rally, hundreds of people protested on the highway near Moncloa Palace, the prime minister’s residence in Madrid. The A6 road was closed for about an hour during the protest, but was later reopened after police cleared the area.

A small protest demonstration took place in front of the Spanish embassy in London.

About 400 people involved in the independence push that came to a head in 2017 will benefit from the law, including both separatists and police officers involved in clashes with activists.

Among them is former Catalan president Carles Puigdemont, the leader of the Junts and the mastermind behind the illegal referendum, who now lives in exile in Belgium.

The independence referendum was declared illegal by the courts and led to Spain’s worst political crisis in decades.

According to Spain’s CSIC Research Council, the amnesty will be the largest in Spain since the blanket amnesty for crimes during Francisco Franco’s dictatorship in 1977 and the first amnesty law passed in the European Union since 1991.

Sánchez, who won a parliamentary vote to form a new government on Thursday with 179 votes in favor and 171 against, defended the law and said an amnesty would help defuse tensions in Catalonia. Some of his ministers, including senior PSOE official Felix Bolanos, welcomed the legislation as a way to “heal wounds and resolve the existing political conflict” in the region.

Protesters, including neo-Nazi groups, have demonstrated outside the Socialist Party headquarters in Madrid for 15 consecutive nights since the deal was announced, leading to violent clashes with police and arrests.

In a survey by the polling institute Metroscopia in mid-September, around 70 percent of respondents – 59 percent of them socialist supporters – said they were against the idea of ​​an amnesty.