WASHINGTON (Reuters) - A Pentagon-led preliminary plan to defeat Islamic State was delivered to the White House on Monday and U.S. Defense Secretary Jim Mattis was expected to brief senior administration officials, a Defense Department spokesman told reporters.

U.S. Defense Secretary James Mattis waits to welcome Canada's Minister of National Defense Harjit Sajjan at the Pentagon in Washington, U.S., February 6, 2017. REUTERS/Yuri Gripas

Pentagon spokesman Captain Jeff Davis told reporters that it was the framework for a broader plan and looked at Islamic State around the world, not just Iraq and Syria.

Davis said the plan would define what defeating Islamic State meant and was one that would “rapidly” defeat the militant group.

He added that Mattis would discuss the plan, which is primarily a written one with accompanying graphics, with members of the Cabinet-level Principals Committee.

The review of U.S. strategy comes at a decisive moment in the U.S.-led coalition effort against Islamic State in both Iraq and Syria, and could lead to relaxing some of the former Obama administration’s policy restrictions, like limits on troop numbers. The Trump administration has said defeating “radical Islamic terror groups” is among its top foreign policy goals.

The Baghdad-based U.S. commander on the ground, Army Lieutenant General Stephen Townsend, has said he believes U.S.-backed forces would recapture both of Islamic State’s major strongholds - the cities of Mosul in Iraq and Raqqa in Syria - within the next six months.

Iraqi forces expect a fierce battle against Islamic State to retake Mosul.

In Syria, the United States must soon decide whether to arm Syrian Kurdish YPG fighters, despite objections from NATO ally Turkey, which brands the militia group as terrorists.

The U.S. military-led review includes input from Secretary of State Rex Tillerson, as well as from the Treasury Department and the U.S. intelligence community.

Davis said that in addition to diplomacy, the plan would include a military framework that builds on capabilities and goals on the battlefield.

Experts have said the Pentagon could request additional forces, beyond the less than 6,000 American troops now deployed to both Iraq and Syria, helping the U.S. military go farther and do more in the fight.

They also said the Pentagon may focus on smaller-scale options like increasing the number of attack helicopters and air strikes as well as bringing in more artillery. The military may also seek more authority to make battlefield decisions.