ESKILSTUNA, Sweden — As Khalif Samantar knelt for afternoon prayers at the Eskilstuna Islamic Dawa Center on Christmas Day, he sensed a growing heat and a low, rushing sound coming from a nearby hallway. He focused his mind on the ritual, only to realize seconds later that someone was shouting, “The mosque is on fire!”

Mr. Samantar sprang through an open window and rushed through the snow in his stocking feet for help. Though about 70 people were inside the mosque at the time, no one was injured.

The fire, which gutted the Dawa center, was the worst of three suspected arson attacks on mosques in Sweden over the last 10 days. In the same period, two freighters bearing hundreds of asylum seekers were abandoned by their crews off the coast of Italy, adding to a surge of more than 200,000 migrants to Europe in 2014.

“We left our country as refugees. We were not looking for food or benefits, we were looking for somewhere to feel safe,” said Abdirahman Farah Warsame, the imam at the mosque where the fire occurred on Christmas Day. He is originally from Somalia. “Now that is gone. We have a feeling that society is turning against us.”