BERLIN (AP) — German authorities say they have arrested two Pakistani men accused of being part of a criminal gang engaged in a large-scale tax scam involving emissions certificates.

Prosecutors said Thursday that the 37 and 40-year-old men were arrested Tuesday at Frankfurt Airport after they flew in from Pakistan to give themselves up.

Frankfurt prosecutor Alexander Badle said German authorities issued international arrest warrants in 2014 for the suspects, whose names weren't released.

Along with another Pakistani man, who was sentenced in 2016 to more than 8 years imprisonment, the suspects are alleged to have fraudulently claimed 136 million euros ($150 million) from tax authorities between August 2009 and April 2010.

As in a separate but similar case, the gang used Deutsche Bank to trade the emissions certificates and reclaim taxes they never paid.