Germany had expelled four Syrian diplomats from the embassy of Syria to Germany after two men suspected of spying were arrested,the foreign ministry said on Thursday.

"After the two people suspected of spying for Syria were arrested, I have decided to expel four members of the Syrian embassy in Berlin," German Foreign Minister Guido Westerwelle announced in a statement in Berlin.

Westerwelle said he had summoned Syria's ambassador and notified of him the decision to expulsion of the 4 diplomats, and reiterated the Germany's stance that "the possible action against the Syrian opposition in Germany shall not be tolerated."

Two men put under custody by German police on Tuesday were reportedly known by the name of Mahmoud El A, who is a 47-year-old man with German-Lebanese dual nationalities and the other by the name of Akram O, a 34-year-old Syrian national.

A politician active in the Syrian opposition suffered heavy physical abuse by two unknown attackers men at home late December, as it aroused wide suspicion that the Syrian secret services were behind the attack.