Washington, November 25 (RHC)-- U.S. Defense Secretary Chuck Hagel has been forced to resign under pressure from President Barack Obama less than two years after taking office.

Obama announced Hagel’s departure on Monday, saying that he would stay on as head of the Pentagon until his replacement is confirmed by the U.S. Senate.

The announcement comes just weeks after a spokesperson for Hagel said he intended to remain in his post until the end of Obama’s presidency. Hagel had criticized the Obama administration’s war on the Islamic State in Iraq and Syria, writing in a leaked memo last month that the president’s policy could implode over a lack of clarity on Syrian President Bashar al-Assad.