Retired US Marine Gen. John Allen, who was selected by President Obama to lead his country’s military efforts against Islamic State in Syria and Iraq, announced on Tuesday that he will leave his post in the coming weeks. Sources close to the ex-general said the main reason behind his step was frustration with the White House’s handling of the war and the lack of resources needed for the campaign. He had asked for deployment of US special forces in Syria and Iraq to help identify targets for air strikes, but the Obama administration turned down his request. The White House said Allen stepped down in order to deal with health matters within his family. Allen’s chief of staff, Karin von Hipple, is also leaving.