The U.S.-led coalition has launched airstrikes on an oil field in Syria's eastern province of Deir el-Zour that borders Iraq, activists reported. The Britain-based Syrian Observatory for Human Rights said the coalition launched four airstrikes on oil wells in the Jafra field late Wednesday.The Local Coordination Committees, an activist group, also reported the airstrikes on Thursday.The U.S.-led coalition has aggressively targeted ISIS-held oil facilities in Syria, which provide a key source of income for the militants. But such strikes also endanger civilians, which could undermine long-term efforts to destroy the militant group.The Observatory, which relies on a network of activists around the country, said that since the airstrikes on Syria began a month ago, 553 people have been killed including 32 civilians. The rest were mostly ISIS militants.