A police car is parked in front of a mosque in Uppsala, Sweden Jan. 1, 2015. A Molotov cocktail was thrown at the mosque early Thursday. No one was hurt and the fire burnt itself out, local media reported. Reuters/Pontus Lundahl

A mosque in Sweden’s fourth largest city, Uppsala, was attacked on Thursday in what authorities believe to be the third arson attack on a Muslim center in the country within a week. Swedish police said that it had launched a manhunt after the latest attack.

Police reportedly said that local people saw a man throwing a burning object toward the mosque. However, the building did not catch fire. The suspect also left a text on the mosque’s door, expressing his “contempt for religion,” according to a police official.

“Someone threw a firebomb, a Molotov cocktail, at the [mosque] building,” a police spokesperson reportedly told Sweden’s TT news agency on Thursday, adding that the mosque was empty when the attack took place and no one was hurt.

“The crime has been classed as attempted arson, vandalism and incitement to hatred,” the police said, requesting witnesses to come forward, Agence France-Presse (AFP) reported.

The attack follows another incident on Monday, when a fire broke out at a mosque in the southern town of Eslov. An earlier Christmas Day attack on another mosque in Eskilstuna city, 86 miles west of the Swedish capital Stockholm, had wounded five people, raising concerns over threats by arsonists. Following the attack, the Swedish government urged citizens to eliminate xenophobia and protect religious freedom.

“The most important thing now is that everyone distances themselves from this,” Sweden's Prime Minister Stefan Loefven told AFP after Thursday’s attack. “In Sweden no one should have to be afraid when they practice their religion.”

The attacks come amid a fierce immigration debate in the Scandinavian country as the Sweden Democrats, an anti-immigrant populist party, intensifies its campaigns.

According to the U.S. Department of State, there are an estimated 475,000 people belonging to the Muslim community residing in Sweden, while the officially sanctioned Muslim Council of Sweden reported that only 106,327 of them actively follow their religion.