Riots broke out in a predominantly immigrant neighborhood of Stockholm Monday night, as residents clashed with police officers and set vehicles on fire, Swedish police say.

Officers were forced to call in reinforcements when a crowd began to gather in the suburb of Rinkeby during the arrest of a suspect, according to a statement from Stockholm police.

Stockholm regional police chief Ulf Johansson said the clashes may have been a result of their “increased pressure on criminals in the area.”

The clashes come days after US President Donald Trump suggested that immigrants in Sweden were to blame for an increase in crime across the country.

In recent years, Sweden has taken in more refugees per capita than any other European country, which has fueled tensions and caused a rise in anti-immigrant sentiment.

Warning shots fired by police

On Monday night in Rinkeby, several people threw stones at police, striking one officer in the arm. As the situation escalated, police fired warning shots to disperse the crowd and one shot at a rioter, a police spokesperson told CNN’s Ivan Watson.

More riots erupted later in the evening, causing damage to shopfronts as well as instances of looting. A police spokesperson said 10 cars had been torched, but that order and security had been restored by midnight.

A CNN team in the area on Tuesday saw evidence of the damage: The doors of Rinkeby’s subway station had been smashed, and other broken windows were covered in temporary plastic sheeting, but the burned-out cars had already been cleared away.

The area is known for its large immigrant population, but also for high levels of unemployment, Watson said.

Authorities have launched an investigation into the unrest.

“Of course it is very serious that the police officers are attacked when doing their job,” Johansson said.

He added: “But I can assure that we are resilient and will not leave, rather intensify our work.”

Large-scale riots in 2013

In an emailed statement to CNN, Swedish police said that while riots like those on Monday night are unusual, it is not the first time unrest has broken out in Rinkeby.

In 2013, large scale riots flared for a week in the Swedish capital, with gangs setting fire to schools and a police station. In 2015, more than 160,000 people — many from Iraq, Syria and Afghanistan — arrived in Sweden seeking asylum.

The country granted asylum to 101,025 refugees — about 1% of the total population — from 2012 to 2015.

In January 2016, a 22-year-old woman was murdered at the asylum center where she worked, leading to pressure on the government to curb the number of migrants coming into the country.

Trump links migrants and crime

At a rally in Florida on Saturday, the US President remarked: “You look at what’s happening last night in Sweden. Sweden, who would believe this? Sweden. They took in large numbers. They’re having problems like they never thought possible.”

However, a former US ambassador told CNN that the country is perfectly safe regardless of the influx of refugees in recent years.

“The crime rate has not skyrocketed,” Azita Raji told CNN’s Chris Cuomo, citing data showing a weak correlation between terrorism and the migrations. Trump’s statements left many Swedish residents puzzled. Djamel Zeghachov, a driver in Stockholm, told CNN: “We were like, what’s happened right now? Has somebody stolen our meatballs? People were laughing about it.”