President Obama has chosen retired Marine Corps Gen. John Allen to lead the effort to destroy the Islamic State in Iraq and Syria, U.S. officials said Thursday. During the Bush administration, Allen helped create the Anbar Awakening in Iraq in 2007, according to Defense One.

Allen was able to lead efforts that rallied the Sunnis in Iraq against al Qaeda. Allen retired last year as a four-star general after 38 years of service, including his role as top U.S. commander in Afghanistan. He's now a distinguished fellow at the Brookings Institution in Washington.

Following his tenure in Afghanistan, Allen, 61, served as an advisor to President Obama and to Secretary of State John Kerry. 

Following the recent beheadings of U.S. journalists James Foley and Stephen, Allen wrote in Defense One urging the president to act as quickly as possible in both Iraq and Syria: “If all the actions of the Islamic State, or IS, to date weren’t sufficiently reprehensible, this act and the potential for other similar acts will snap American attention with laser-like focus onto the real danger IS poses to the existence of Iraq, the order of the region, and the homelands of Europe and America,” Allen wrote.

The U.S. is already conducting targeted airstrikes in Iraq against the Sunni militant group and will most likely extend those strikes to Syria with the support of dozens of international allies. According to a report by the Washington Post, Obama has told the Pentagon to kill Islamic State leaders with its airstrikes. Allen will be responsible for coordinating the efforts among the ally countries and ensuring that the strategy Obama put forward in his speech Wednesday night is realized.