BERLIN (AP) — Germany says it is expelling four Syrian diplomats following the arrest earlier this week of two men accused of spying on Syrian opposition groups in Germany.

Foreign Minister Guido Westerwelle said in a statement Thursday that he ordered the expulsions of the four Syrian Embassy employees, and that the ambassador had been informed. He did not give details on the diplomats.

German federal prosecutors said Tuesday they had arrested a Syrian and a German-Lebanese dual national on suspicions that they spied on Syrian opposition supporters in Germany over several years.

Syria’s ambassador to Germany was summoned to the Foreign Ministry the same day and told that Berlin cannot tolerate such activities.