Germany is reiterating its laws against polygamy and underage marriages as the increase in migrants from Muslim countries has led to a rise in relationships the country does not recognize, BBC reported Wednesday.

“No one who comes here has the right to put his cultural values or religious beliefs above our law,” Justice Minister Heiko Maas told the German tabloid Bild, according to the BBC.

Polygamy is banned by law in Germany, and the minimum marriage age is 18. It is possible for a 16-year-old or 17-year-old to marry if their family consents, the BBC reported, but the other person has to be at least 18 for the marriage to be legal.

In some Islamic countries, men often have multiple wives or marry girls who are still children. Concern over these marriages has grown in Germany as the country has accepted hundreds of thousands of refugees and migrants, most of them from the Middle East and Africa.

Over the past year, Germany and other countries in Europe have started to grapple with how to integrate so many new people into their economy and culture. This has sometimes been challenging in the face of terror attacks in Paris, Brussels and in the United States, and attacks on women in Germany, all of which have stoked fears and in some cases anti-Muslim backlash.

While Germany has clear laws against individuals being married to more than one person at a time, the country has quietly allowed polygamous relationships to exist, according to the BBC. This can be revealed, for example, when a man dies and his inheritance is split between his two wives.

Maas, the justice minister, wants that to change.

“Everybody must abide by the law, no matter whether he has grown up here or has only just arrived,” he told Bild, adding that this policy also applies to forced and underage marriages. “We cannot tolerate forced marriages, above all if they affect underage girls.”

The German state of Bavaria has registered 550 cases of married girls under the age of 18, and 161 under 16 years old, among recent asylum seekers, the tabloid reported. Underage marriage is outlawed by the United Nations'  Convention on the Elimination of All Forms of Discrimination Against Women, and the right to free and full consent from both parties is part of the Universal Declaration of Human Rights.

Still, most of these marriages in Germany took place before the girls migrated to Europe. Because there is no clear law on how to treat underage or polygamous marriages made in other countries, German courts have been making judgments on a case-by-case basis.