BERLIN—The number of crimes committed by migrants surged 52.7% in Germany last year, new statistics said, fueling a sharp rise in violent offenses and highlighting the challenges facing Chancellor Angela Merkel and other pro-immigration politicians in coming elections.

Migrants, defined as refugees and rejected asylum seekers, committed 174,438 crimes in 2016, up from 114,238 a year earlier, according to police figures released Monday. Over the same period, crimes committed by German citizens declined 3.4% to 1.41 million.

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