Secretary of State Rex Tillerson said Sunday it's time for Iranian "foreign fighters" to leave Iraq, now that Islamic State militants are nearing defeat.

"Iranian militias that are in Iraq, now that the fight against Daesh and ISIS is coming to a close, those militias need to go home," Tillerson said during a press conference in Saudi Arabia.

"The foreign fighters in Iraq need to go home and allow the Iraqi people to regain control," the former CEO of Exxon Mobile said.

Tillerson was in Saudi Arabia to attend a launch meeting of the Saudi Arabia-Iraq Coordination Committee. The Saudis are seeking to woo majority-Shiite Iraq out of Iran's orbit.

Saudi Arabia and Iran are engaged in a regional power struggle, backing opposite sides in Syrian and Yemeni civil wars that are heavily influenced by religious identity.

Although adversaries, Iranian military advisers and Iran-backed Shiite militias fought on the same side as the U.S. by supporting Iraq's central government after Islamic State militants overran much of the country in 2014. There are thousands of American troops currently in Iraq.

Tillerson left Saudi Arabia on Sunday to visit nearby Qatar, a small but wealthy peninsular country that's in an ongoing dispute with a coalition of Arab countries led by Saudi Arabia, which accuses the emirate of funding terrorists and being too friendly with Iran.

"In my meetings with [Saudi] Crown Prince Mohammed bin Salman, I asked him to please engage in dialogue, [but] there is not a strong indication that parties are ready to talk yet. We cannot force talks upon people who are not ready to talk," Tillerson reportedly said at a press conference in Qatar.