German Chancellor Olaf Scholz (Photo: AP)

The demand from Scholz came just days after sources said Germany summoned the Polish ambassador and Interior Minister Nancy Faeser spoke to her Polish counterpart on the topic.

German interior ministry spokesman Mehmet Ata told reporters that Berlin was seeking information from Warsaw about how many visas were issued and when, as well as the nationalities of the recipients.

Since earlier this month, the Polish government has been facing accusations by opposition parties that it was complicit in a system in which migrants received Polish visas at an accelerated pace without proper checks after paying intermediaries.

Arrivals to Poland could easily cross into other European Union countries given that borders are open.

Poland's secret service said last week that seven people had been detained in the scandal. Polish Deputy Foreign Minister Piotr Wawrzyk resigned last week.