Air Force Gen. Lori Robinson becomes the first female head of a combatant command at a ceremony attended by Defense Secretary Ashton B. Carter. (Reuters)

PETERSON AIR FORCE BASE, Colo. — Air Force Gen. Lori J. Robinson became the first woman ever to lead a U.S. military combatant command Friday, taking over U.S. Northern Command at a time when the Pentagon is bolstering security at home in light of threats posed by the Islamic State and homegrown terrorism.

Robinson, previously the commander of Pacific Air Forces, also will lead the North American Aerospace Defense Command (NORAD) from headquarters in the foothills of Pikes Peak. Northern Command (NORTHCOM) was created in 2002 after the Sept. 11, 2001, attacks to protect the United States and also oversees security cooperation with Canada, Mexico and the Bahamas. NORAD includes U.S. and Canadian troops and has controlled aerospace over North America since the early days of the Cold War.

Robinson, speaking to several hundred people at a change of command ceremony here, called her new job a “significant responsibility” and credited her father, George Howard, a retired 30-year Air Force officer, with being her role model. Several other women have served as four-star officers in the U.S. military, but none had ever led a combatant command. To date, none has ever served as a service chief.

“I pledge to devote my full energy and full focus to this job,” Robinson said.

Defense Secretary Ashton B. Carter said she has a proven track record for managing complex military operations. She replaces Navy Adm. William Gortney, who is expected to retire.

“Lori’s ability to lead, inspire and command respect across our joint force reflects her understanding that, no matter the complexity of our platforms or the power of our technology, it is our people always come first,” Carter said.

“The fact that General Robinson is the first female COCOM [combatant commander] is a good sign, because there are women officers of her quality in our officer corps now from whom the president and I can select our senior military leaders. She was selected because she was the most qualified officer for this job.”

The Pentagon chief outlined several ways that the U.S. military has stepped up security at home recently, citing attacks in Chattanooga, Tenn., in August that killed four Marines and a U.S. sailor and were inspired by the Islamic State. The military increased protection at bases and off-base installations, putting in place stronger security systems, reinforced doors and new ways to escape facilities, Carter said.

“We’re also introducing a mass warning and notification capability to broadcast threats quickly and broadly, notifying [Defense Department] personnel within a 20-mile radius of a threat within 10 minutes,” he said. “That’s a direct response to Chattanooga, where the killer targeted two facilities 11 minutes a part in a span of 12 minutes.”

Robinson joined the Air Force in 1982 after graduating from the University of New Hampshire. She became a brigadier general in 2008, rising quickly through the senior officer ranks afterward. She is married to a retired two-star officer, Maj. Gen. David A. Robinson.

Robinson, asked previously about becoming one of the few female four-star officers in history, said that her earlier assignments prepared her to lead U.S. troops.

“As far as the woman part of it all, as I often say to people, I’m the commander of Pacific Air Forces, I’m a general in the United States Air Force, I’m an airman, and I happen to be a woman,” she told reporters in Washington in November.