WASHINGTON, June 11 -- The addition of up to 450 U.S. military personnel and the opening of a training base in Iraqare an adjustment to the campaign against the Islamic State (IS), the Pentagon said on Thursday.

The adjustment fits in with the strategy to enable Iraqi forces to take the fight to the IS, Martin Dempsey, the chairman of U.S. Joint Chiefs of Staff, said in a press release.

"The military campaign is based around training and equipping," Dempsey said. "That's the centerpiece, with kinetic strikes from the air being an enabler for the Iraqi force."

The base will expand the U.S. footprint in Anbar province and allow American trainers to work with the Iraqi army's 8th Division, he said. It also will allow Americans to train and supply Sunni tribes that want to fight against IS.

There is no timetable for any offensive in the province and the main effort in the country must come from Iraqi security forces, Dempsey said. Local tribes will help to "thicken" the lines against IS and will help to govern areas liberated from the terror group, he said.

This will take time, Dempsey said, adding that establishing the base also will take time.

U.S. service members will probably deploy there from troops already in Kuwait, he said, and they must establish the command and control architecture, the force protection system and the intelligence structure.

However, the base in Iraq's Anbar province is not a game- changer, Dempsey said. "The game changers will have to come from the Iraqi government itself."

On Wednesday, the White Houseannounced that President Barack Obamahas authorized the deployment of up to 450 more American troops to Iraq to train and assist the Iraqi forces battling the IS extremist group.

Analysts believed that the decision was based on the fact that despite daily air strikes on IS positions, the Iraqi security force have failed so far to stem the advance of the extremist group which took over Anbar provincial capital of Ramadi last month.

Sabah al-Sheikh, a professor of Baghdad University, expressed his doubt that the deployment of some 450 U.S. troops at al- Taqqadum base in eastern Anbar province could be the beginning of the return of U.S. occupation to Iraq.

Earlier, the fall of Ramadi to the IS militants on May 17 pushed U.S. Defense Secretary Ashton Carter to blame the Shiite- dominated security forces for their lack of "will to fight" in the battle for the Sunni city of Ramadi as the Iraqi soldiers "vastly outnumbered" the IS attackers.