The debate over immigration raged on Monday in both the US and Germany.

President Donald Trump came under fire from Democrats and Republicans over his immigrant detention policies, after about 2,000 children were separated from their parents at the US-Mexico border.

But amid the mounting criticism, the president took time to swipe at Germany’s immigration policies in a series of tweets about German Chancellor Angela Merkel’s open-door migration law.

“Big mistake made all over Europe in allowing millions of people in who have so strongly and violently changed their culture!” he wrote.

Merkel is currently facing pressure from conservative leaders to restrict migration laws — and if she doesn’t resolve the issue, she could soon lose power.

Merkel’s coalition partners handed her an ultimatum on Monday to mend the country’s immigration regulations within the next two weeks. Her main opposition comes from Germany’s Interior Minister Horst Seehofer, chair of the conservative Christian Social Union party, who has advocated for turning away migrants who have already applied for asylum in another European Union country or were denied entry.

After Merkel’s two weeks are up, Seehofer claims he will follow through with a unilateral plan to start rejecting asylum seekers.

Back in 2015, Merkel enacted an open-door policy to take in refugees fleeing war from Syria, Iraq, and Afghanistan, reportedly taking in more than 1.4 million people; now about 10,000 immigrants flow in each month. All asylum seekers are allowed to enter the country while they wait for their cases to be reviewed.

Germany’s intense immigration debate is an issue for Merkel, who is reaching out to other European leaders to find countries that could potentially take in the migrants Germany turns away. But with the approaching deadline, and Merkel’s power being threatened by government leaders like Seehofer, it’s unclear what her next move will be.

Merkel’s power is at stake

In February, Germany’s two largest political parties — the center-left Social Democratic Party and the combined center-right Christian Democratic Union, or CDU, and the Christian Social Union, or CSU — renewed a coalition agreement to create a majority party in parliament with Merkel at the helm. The CSU governs the German state Bavaria, while the CDU, which is Merkel’s party, governs the country’s other 15 states.

But now that Seehofer’s party and Merkel’s party are fighting over Germany’s immigration laws, it could lead to the dissolution of the coalition and a government breakdown.

Germany’s migration issues are also at the heart of a massive immigration debate within the European Union.

Early last week, a boat carrying more than 600 African migrants was turned away from Italy, a country that has recently pledged to enforce stricter migration laws; after it was stranded for two days at sea between Malta and the Italian island Sicily, Spain’s Prime Minister Pedro Sánchez allowed it to dock in Valencia on Sunday.

And Italy isn’t alone with its recent wave of anti-immigration sentiment. Both Italy and Austria are reportedly critical of Merkel’s open-door policies toward migrants, and support Seehofer’s pursuits to restrict the German border.

Although it’s uncertain how Merkel will respond in light of her power struggle, it’s evident that Germany’s immigration issues are fueling a much larger discussion surrounding immigration within Europe.