The U.S. is sending as many as 1,300 more troops to Iraq in late January, the Defense Department announced Friday. The troops will include about 1,000 soldiers in the Army’s 82nd Airborne Division. The rest will be drawn from multiple services.

“Their mission will be to train, advise and assist Iraqi security forces,” Rear Adm. John Kirby, the Pentagon press secretary, told reporters at a briefing. “This deployment is part of the additional 1,500 troops that the president authorized in November.”

Defense Secretary Chuck Hagel signed orders Wednesday for the first group of these troops to go to Iraq, the Associated Press reported.

“What makes this [deployment] different is simply the geography,” Kirby noted, pointing out the advising teams will operate in the Anbar area and north of Baghdad.

Pentagon officials said last month military advisers would establish training sites across Iraq in a major expansion of the American military campaign against the Islamic State in Iraq and Syria, as the New York Times reported.

The latest surge in troops will come after two senior Islamic State group leaders were killed by American-led coalition airstrikes in Iraq during the past week, according to an unnamed U.S. official cited by AP. The airstrikes killed a key deputy of Abu Bakr al-Baghdadi, the leader of the extremist group formerly known as ISIS, as well as one of the group’s military chiefs. Also killed was a third militant, identified as a mid-level leader, AP said.