He ordered the ELAS commander Markos Vafiadis to abandon guerrilla warfare tactics and adopt a strategy of conventional warfare: according to Vafiadis, this had a strongly negative effect on ELAS.[3] Vafiadis was expelled from the KKE for challenging Zachariadis and kept under house arrest in Albania, accused of being a British agent.[3] During the Greek civil war, Zachariadis ordered also the assassination of various left-wing opponents of the KKE, particularly in Athens.[4]