BERLIN (Reuters) – The number of migrant criminal suspects in Germany soared by more than 50 percent in 2016, data from the Interior Ministry showed on Monday – a statistic that could boost support for the anti-immigration party five months ahead of a federal election.

More than a million migrants have arrived in Germany in the last two years. Fears about security and integration initially pushed up the poll ratings of the right-wing Alternative for Germany (AfD), but the party’s support has slipped as the rate of arrivals has slowed.

The number of suspects classed as immigrants – those applying for asylum, refugees, illegal immigrants and those whose deportation has been temporarily suspended – rose to 174,438, 52.7 percent more than the previous year.

The number of German suspects declined by 3.4 percent to 1,407,062.

Interior Minister Thomas de Maiziere said crimes committed by refugees had “increased disproportionately” last year and warned: “Those who commit serious offences here forfeit their right to stay here.”

But he said some migrants committed multiple offences, distorting the statistics, and that most migrants lived peacefully and obeyed German law.

Migrants accounted for 8.6 percent of all crime suspects in Germany in 2016, up from 5.7 percent the previous year.

De Maiziere said one reason for the high crime rate among migrants was likely to be their accommodation situation. In 2016 many were living in makeshift shelters or sharing crowded rooms.

The number of attacks on refugee homes has declined for the first time since data started being collected in 2014. Some 995 were carried out in 2016, compared with 1,031 the previous year.

Crimes motivated by Islamism increased by 13.7 percent, the report showed. In December a failed Tunisian asylum seeker who had pledged allegiance to Islamic State drove a truck into a Berlin Christmas market, killing 12 people.

(Reporting by Michelle Martin; editing by Andrew Roche)