Despite the frequent use of economic and military-specific sanctions against countries affected by civil conflicts, little is known about the possible impact that these coercive tools have on conflict dynamics. This article examines how threats and imposition of international sanctions affect the intensity of civil conflict violence. We formulate and test two competing views on the possible effect of economic and military-specific sanctions on conflict dynamics by combining data on fatalities in battle-related violence in all internal armed conflicts in Africa from 1989 to 2005 with data on economic sanctions and arms embargoes. The results indicate that threats of economic sanction and arms embargo are likely to increase the intensity of conflict violence. Similarly, imposed economic sanctions are likely to contribute to the escalation of conflict violence. Imposed arms embargoes, on the other hand, are likely to reduce conflict violence. We conclude that international sanctions appear to be counterproductive policy tools in mitigating the human cost of civil conflicts unless they are in the form of imposed arms embargoes attempting to limit the military capacity of the warring parties.