Retired Marine Gen. John Allen will coordinate the broad international effort to battle the Islamic State militants, as the campaign against the extremist group ramps up and nations begin to determine what role each will play, U.S. officials said Thursday.

Allen, who has been serving as a security adviser to Secretary of State John Kerry, is expected to work with the nearly 40 nations around the world who have agreed to join the fight and help them coordinate what each will contribute, several officials told The Associated Press.

The officials spoke about Allen’s expected appointment on condition of anonymity because they were not authorized to discuss the matter ahead of an announcement.

Allen comes to the job with vast experience coordinating international allies on the warfront. He served as deputy commander in Iraq’s Anbar province from 2006 to 2008, working with Arab partners on organizing the Sunni uprising against al-Qaida. He moved from there to serve for two years as the deputy commander of U.S. Central Command, which oversees military troops and operations in the Middle East, North Africa and Central Asia.

Allen next became the top U.S. commander in Afghanistan from 2011 to 2013, where he worked with international allies who sent troops to the battlefield.

As a result of his experience, Allen is very familiar many of the Middle East nations and leaders considered crucial to the latest effort to degrade and destroy the Islamic State group militants who have seized control of portions of Iraq and Syria in a ruthless reign of terror. He also has worked closely with most of the key military and diplomatic leaders, including Gen. Lloyd Austin, the current head of U.S. Central Command, who will oversee America’s military campaign.

President Barack Obama announced Wednesday night that the U.S. will be expanding airstrikes in Iraq and into Syria, in an aggressive move to root out the Islamic State group extremists where ever they are. Obama, Kerry and Defense Secretary Chuck Hagel have spent the last week meeting with international leaders overseas in an effort to build a broad coalition of nations — particularly Arab countries in the region — to aid the fight.

Officials are looking for partners to help train moderate Syrian rebels, work with the Iraqi security forces, contribute equipment, ammunition, intelligence, logistics and funding, as well as possibly also launch airstrikes.

(AP)