PRAGUE (Reuters) -Slovakia has decided to expel three Russian embassy staff based on information from the secret service and they must leave the country within 72 hours, the foreign ministry said on Monday. “The Ministry of Foreign Affairs… at the same time strongly urges the Embassy of the Russian Federation that their representatives perform their activities in line with the Vienna Convention on Diplomatic Relations,” it said in a statement. The ministry did not give any details. Slovak news website http://www.dennikn.sk said without citing its sources that police arrested at least three S…