Defense Secretary Jim Mattis speaks at a news conference during the NATO Defense Ministers Council meeting in Brussels on Feb. 16, 2017.(Photo: Stephanie Lecocq, European Pressphoto Agency) Defense Secretary Jim Mattis made an unannounced visit to Iraq on Monday after offering assurances that the United States does not intend to seize the country's oil. His comments, made hours before he arrived in Baghdad, may calm Iraqi leaders alarmed by remarks President Trump made about seizing the country's oil to pay for U.S. military help in the country. “I think all of us here in this room, all of us in America have generally paid for our gas and oil all along, and I’m sure that we will continue to do that in the future,” Mattis told reporters traveling with him, according to the Associated Press. “We’re not in Iraq to seize anybody’s oil.” Mattis arrived in Iraq just as U.S.-backed Iraqi forces launched a new offensive to retake the remaining portions of Mosul, Iraq's second largest city, from Islamic State control. Iraqi ground forces on Sunday began to clear the militants from the western part of the city, the militants' last major stronghold in Iraq. There are more than 5,000 U.S. troops in Iraq, providing Iraqi forces advice, training and support. A U.S.-led coalition also is conducting airstrikes to support the ground war against the Islamic State. Mattis' key goal during the visit to Iraq is to speak about the military operations with political leaders and commanders on the ground, including his top commander in Iraq, Lt. Gen. Stephen Townsend, the AP said. Ownership of Iraq's oil is a sensitive issue. Trump brought it up during the campaign, and he mentioned it again late last month during a visit to the CIA. “To the victor belong the spoils,” Trump told members of the intelligence community. He said he first argued this case for “economic reasons,” but added it made sense as a counter-terrorism approach to defeating the Islamic State “because that’s where they made their money in the first place.” “So we should have kept the oil,” he said. “But, OK, maybe you’ll have another chance.” The militant group has raised untold millions of dollars by seizing Iraqi oil and selling it on the black market. The visit was Mattis' first to Iraq as defense secretary, but he has long experience in the country. Mattis commanded troops during the 2003 U.S.-led invasion of Iraq that ousted dictator Saddam Hussein. He also led Marines in restive Anbar province in western Iraq, and later headed U.S. Central Command, which oversees U.S. military operations in the Middle East.