Angela Merkel delivers her speech in Delbrueck | Friso Gentsch/AFP via Getty Images Angela Merkel: Europe needs coherent foreign policy German chancellor calls for a common EU stance on China and Russia as well as more solidarity on migration.

The biggest challenge facing the European Union in the coming years will be to forge a coherent foreign policy, German Chancellor Angela Merkel said in an interview published Sunday.

Merkel, who is poised to win a fourth term in Germany's parliamentary election later this month, also expressed hope that a solution to the impasse over the distribution of migrants across the EU would be found in the "not too distant future."

In the interview with German newspaper Frankfurter Allgemeine Sonntagszeitung, she said EU member countries urgently need to find a common stance toward China and Russia.

"The world has to see that member states won't deviate from a European consensus on these issues," she said, adding that it was important to recognize that a country's position would sometimes be overruled in favor of the bloc's.

To help end the stand-off over the distribution of migrants across the bloc, the EU should "stabilize" all other elements of migration policy, by securing borders, developing a partnership with Africa and putting more pressure on smugglers, Merkel said. The success of its migration policy would also depend on EU countries' willingness to show solidarity "with no if and buts," she said.

Merkel also had stern words for Turkish President Recep Tayyip Erdoğan. "What we are experiencing at the moment with German citizens in Turkish custody is serious and absolutely unacceptable," she said, adding that Turkey is slipping further away from Europe and its values.

For now, it is pointless to negotiate with Turkey on expanding the customs union it shares with the EU, and time to decide whether EU accession talks should be suspended or even ended, Merkel said. "There are a number of options on the table," she added.

More generally, Merkel warned against resignation in the face of injustice, saying: "When I hear, for example, that we should just accept Russia's annexation of Crimea, I wonder: What would have happened if the question of the GDR [communist East Germany] was handled in that way, if people had said, 'Well of course, Germany will stay divided, that won't change.'"

Last month, the leader of the liberal Free Democrats, Christian Lindner — a possible coalition partner for Merkel after the election — called for Germany to see the annexation of Crimea as a "permanent provisional solution."

Merkel also called on politicians to guard against lazy language in political debate: "I've always said, 'Don't talk about the Greeks, the Italians, the French. They are all individuals' ... We have to guard against stereotypes."