BAGHDAD, Iraq (CNN) -

U.S. President Barack Obama on Tuesday authorized additional troops be deployed to Iraq to protect American diplomatic facilities and personnel in Baghdad.

The 350 troops are being sent at the request of the U.S. Department of State to beef up security, an appeal that comes as the violence mounts as Iraqi security forces battle ISIS fighters and their Sunni militant allies.

"The request he approved today will allow some previously deployed military personnel to depart Iraq, while at the same time providing a more robust, sustainable security force for our personnel and facilities in Baghdad," according to a statement released by the White House.

The new troops will bring the number of American troops in Iraq to well over 1,000, with most serving either as diplomatic security or military advisers to Iraq's security forces.

Even as the Pentagon and the White House stressed the new troops were not being sent to Iraq in a combat role, they will be arriving at a critical time.

Iraqi forces, aided by U.S. military airstrikes, have begun to make gains against ISIS, which calls itself the Islamic State.

U.S. airstrikes hit ISIS targets

The strikes destroyed or damaged what the Pentagon described as 16 ISIS armed vehicles near the Mosul Dam, which was retaken last month by Iraqi and Kurdish forces.

Obama authorized targeted airstrikes last month to protect U.S. personnel in Iraq -- including military advisers -- as well as minorities being brutalized by ISIS.

The additional U.S. troops will include "a headquarters element, medical personnel, associated helicopters and an air liaison team and helicopter crews," Pentagon Press Secretary Rear Adm. John Kirby said.

"This action was taken at the recommendation of the Department of Defense after an extensive interagency review and is part of the President's commitment to protect our personnel and facilities in Iraq as we continue to support the government of Iraq in its fight" against ISIS.

Families of missing soldiers demand answers

Even as the United States beefed up its own security at the Embassy, the families of missing Iraqi security force members stormed Parliament on Tuesday to demand answers about the fate of their loved ones.

More than 100 family members clashed with security before entering the building, located in the International Zone, commonly known as the Green Zone. They vandalized the interior and became aggressive with people inside, , a parliamentary official told CNN.

They are refusing to leave until their concerns are addressed.

The families are angry over the lack of information about the victims of an alleged massacre of Iraqi forces and cadets near Tikrit, when a military base formerly known as Camp Speicher was overrun by ISIS in June.

In recent weeks, family members of the recruits have been protesting outside the International Zone. Some have met with lawmakers.

They want the bodies of their sons returned to them for burial, and they want the missing to be brought back.

The killings at Camp Speicher are among the worst atrocities claimed by ISIS in Iraq. The group, which refers to itself as the "Islamic State," said it killed 1,700 Iraqi forces, but no official figures have been released.

A senior health official told CNN at the time that more than 1,000 families have registered that they had sons at the camp.