Abbas came into conflict with Palestinian militant groups, notably the Palestinian Islamic Jihad Movement and Hamas because his pragmatic policies were opposed to their hard-line approach. Initially, he pledged not to use force against the militants in the interest of avoiding a civil war, and attempted negotiation. This was partially successful, resulting in a pledge from the two groups to honor a unilateral Palestinian cease-fire. However, continuing violence and Israeli "targeted killings" of known leaders forced Abbas to pledge a crackdown in order to uphold the Palestinian Authority's side of the Road map for peace. This led to a power struggle with Arafat over control of the Palestinian Security Services; Arafat refused to release control to Abbas, thus preventing him from using them on the militants. Abbas resigned as prime minister in September 2003, citing lack of support from Israel and the United States as well as "internal incitement" against his government.