German Chancellor Olaf Scholz on Friday spoke with his Polish counterpart Donald Tusk, after criticism from Warsaw over Germany’s plan to introduce further checks on its borders. The two leaders agreed in a call that the challenges posed by illegal migration and smuggling could only be overcome in unison, and that close cooperation between European partners is essential, government spokesman Steffen Hebestreit said in Berlin. Hebestreit said Scholz gave Tusk explanations over his government’s new “migration policy measures,” which are due to be implemented from Monday at Germany’s borders with…