About 90 Special Forces troops arrived in Baghdad Tuesday to begin an advisory mission to the Iraqi military that could lead to airstrikes against Islamic militants now controlling large swaths of northern and western Iraq.

The 90 Special Forces troops were joining 40 troops pulled from assignments at the U.S. Embassy in Baghdad to set up a Joint Operations Center with the Iraqi military. An additional 50 Special Forces troops were expected to arrive in Baghdad in the next several days, said Rear Adm. John Kirby, the Pentagon press secretary.

President Obama has authorized up to 300 Special Forces troops from U.S. Central Command deploy to Iraq to aid the crumbling Iraqi military fighting the advancing forces of the Islamic State of Iraq and the Levant.

Kirby stressed that the Special Forces troops would be working with the Iraqis at the headquarters and brigade levels.

"We're not talking about putting people out on foot patrols at the platoon level," Kirby said.

Although Obama has authorized 300, "that doesn't necessarily mean that there will be 300" actually on the ground in Iraq for what has been called a mission of limited duration, Kirby said.

"I don't have a list of criteria for you" concerning when the mission might end, Kirby said at a Pentagon briefing.

He said the initial task for the newly-arrived troops will be to assess the situation on the ground with the aid of intelligence from 30-35 daily surveillance flights over Iraq by manned and unmanned aircraft.

"The President also made clear that airstrikes are not off the table. We remain postured to do that," Kirby said.

Last week, the Navy moved the aircraft carrier George H.W. Bush with more than 50 F/A-18 Super Hornet attack aircraft aboard into the Persian Gulf.

The U.S. also has numerous air assets in neighboring Saudi Arabia and Kuwait, and in the Gulf state of Qatar, but it was unclear if those states would permit airstrikes from their territory.

The Bush and her two escort warships – the cruiser Philippine Sea and the destroyer Truxtun -- have since been joined in the Persian Gulf by the amphibious transport dock ship Mesa Verde with five MV-22 Osprey tilt-rotor aircraft and approximately 550 Marines from the 22nd Marine Expeditionary Unit (MEU) aboard.

The Special Forces troops arrived amid conflicting reports on the status of Iraq's largest oil refinery in the northern town of Baiji. Several reports said that ISIL fighters were in control of Baiji while the Iraqi government claimed that a fight was continuing.

At the Pentagon, Kirby said that Baiji ‘remains contested territory now."

Secretary of State John Kirby on Tuesday was in Irbil, capital of the Kurdish Regional Government in northern Iraq, for talks with Kurdish leaders on Obama's push to form a more inclusive Iraqi government of the Shia, Sunni and Kurdish communities.

As they began talks, Kurdish President Massoud Barzani said the country of Iraq is "facing a new reality and a new Iraq."

"We believe that Baghdad is trying to marginalize us, as was the case with the previous regime (of Saddam Hussein), but the people of Kurdistan have made great sacrifices for their freedom and they would never accept this subjugation," Barzani said.

Kerry carried a message of inclusiveness and urged against the partition of Iraq. Kerry also told reporters that each day was bringing the U.S. more intelligence for potential airstrikes against ISIL.

"The president has moved the assets into place and has been gaining each day the assurances he needs with respect to potential targeting," Kerry said.

-- Richard Sisk can be reached at richard.sisk@monster.com