Candidates in France's pivotal and polarizing legislative elections were making their last pushes on Friday for the second and decisive round of voting after a three-week campaign marked by hate speech, verbal abuse and physical attacks.

French Interior Minister Gérald Darmanin said his ministry has registered 51 verbal and physical attacks against candidates, their deputies or their supporters during campaigning for the high-stakes parliamentary elections that end with the second round of voting on Sunday. Several attacks were “extremely serious,” Darmanin said in an interview with French broadcaster BFM on Friday.

At least 30 suspects “with extremely varied backgrounds” have been arrested, the interior minister said, adding that candidates and their supporters across France’s political spectrum have been targets of verbal and physical abuse.

“National Rally’s candidates were violently attacked … (as were) left-wing candidates,” Darmanin said.

Tensions are high as left-wing and moderate groups try to prevent the anti-immigration, nationalist National Rally from winning an absolute legislative majority, which would be a first and a major historical shift for France.

The National Rally, under party president Jordan Bardella, secured the most votes in the first round of the legislative elections on June 30 but not enough to claim an overall victory that would allow the formation of France’s first far-right government since World War II.

Darmanin said 30,000 police officers will be deployed on Sunday, including 5,000 in the Paris region, to ensure that the results of the election “are respected whatever they may be.” He said gatherings outside of the National Assembly, the lower house of parliament, have been banned.

A group called the Antifascist Action Paris-Suburbs called for a protest outside the National Assembly on Sunday night as results come in.

Many people have voiced concerns that the surge in voter support for the anti-immigrant National Rally has made people feel more comfortable using racist, xenophobic and antisemitic language in public.

The government agency tallying racist acts did not have recent data since the brief campaign began.

Candidates have complained of both hate speech and physical violence during the campaign.

Government spokesperson Prisca Thevenot, who is a candidate for the centrist Ensemble alliance led by President Emmanuel Macron, said she and a deputy and a party activist were putting up election posters in Meudon near Paris on Wednesday night when a group attacked them. Thevenot’s deputy and the party activist were taken to a hospital.

Macron called the surprise legislative election on June 9 after his alliance suffered a punishing defeat at the hands of the National Rally in French voting for the European Parliament, plunging the country into a sudden legislative campaign.