Retired Marine Corps Gen. James Mattis, President-elect Donald Trump’s nominee for secretary of defense, testifies at his confirmation hearing before the Senate Armed Services Committee on Capitol Hill in Washington, Thursday, Jan. 12, 2017. (AP Photo/J. Scott Applewhite)
Retired Marine Corps Gen. James Mattis, President-elect Donald Trump’s nominee for secretary of defense, testifies at his confirmation hearing before the Senate Armed Services Committee on Capitol Hill in Washington, Thursday, Jan. 12, 2017. (AP Photo/J. Scott Applewhite) Credit: J. Scott Applewhite

Washington — Retired Marine Gen. James Mattis, Donald Trump’s pick to be the next U.S. defense secretary, placed Russia first among principal threats facing the United States, arguing for greater U.S. support for European allies to counter what he said were Moscow’s attempts to “break” the North Atlantic alliance.

Mattis, a revered combat leader who made his name in the wars following the Sept. 11, 2001 attacks, cautioned that sustained cuts to military budgets and personnel meant that the U.S. military is no longer strong enough to easily outmatch Russia and a host of other threats.

As the president-elect’s other Cabinet picks face intense questioning in their own confirmation hearings, the 66-year-old former officer faced virtually no challenges from members of the Senate Armed Services Committee to his suitability, despite a pending vote that would allow a recent veteran to assume the top Pentagon job.

Mattis’ remarks provide some of the first hints about how the Trump administration, which has not put forward comprehensive national security plans, may alter the posture of the world’s most advanced military.

His comments also suggested some differences in viewpoint with the president-elect, who has repeatedly questioned longstanding military alliances and signaled a willingness to embrace Russian President Vladimir Putin.

If confirmed, Mattis will take control of the Pentagon at a time when it is seeking to complete an extended campaign against the Islamic State in Iraq and Syria while grappling with an array of smaller terror cells and China’s military rise.

Mattis, known for his knowledge of military history and his use of the call sign “Chaos” during overseas deployments, is one of his generation’s most respected military officers. His blunt style has also brought controversy at times, as have his hawkish views on confronting threats in the Middle East.

Mattis was named the head of U.S. Central Command, one of the U.S. military’s most influential positions, in 2010, but left in 2013 amid disagreement with the White House over the general’s desire to intensify the military response to Iranian activities throughout the region.

In documents submitted to lawmakers prior to the hearing, Mattis identified Iran as “the primary source of turmoil” in the Middle East. “Its policies are contrary to our interests,” he said.

Although Mattis’ hawkish views on the danger from Iran appear to coincide with Trump’s, he voiced support Thursday for leaving President Obama’s nuclear deal with Tehran intact.