The U.S. amphibious assault ship Bataan with 1,000 Marines aboard was headed to the Persian Gulf Monday as part of the buildup of U.S. forces in the region to protect Americans and counter the threat to the Iraqi government from Islamic extremists.

Pentagon officials confirmed that the 844-foot Bataan, based in Norfolk, Va., had left the Mediterranean and was expected to join six other Navy warships in the Persian Gulf, including the aircraft carrier George H.W. Bush.

Until earlier this month, the Bataan and the Marines from the 22nd Marine Expeditionary Unit, based in Camp Lejeune, N.C., were on standby off the coast of Libya in case of an emergency at the U.S. Embassy in Tripoli.

The other warships already in the Persian Gulf were the destroyers Arleigh Burke, Truxtun, and O'Kane, the cruiser Philippine Sea, the dock landing ship Gunston Hall, and the amphibious transport dock Mesa Verde.

Pentagon officials also said that Army Maj. Gen. Dana J.H. Pittard had arrived in Baghdad to take charge of the advisory mission to the struggling Iraqi national security forces.

About 180 of the authorized 300 advisors for Pittard's command, most of them from Special Forces units assigned to the Central Command, were on the ground and operating around Baghdad or out of a Joint Operations Center, said Army Col. Steve Warren, a Pentagon spokesman.

Force protection for the advisors moving around Baghdad was a concern, Warren said, but "they are very skilled at protecting themselves.”

The U. S. also intended to set up a Joint Operations Center in northern Iraq but Warren could not say when or where the second JOC would go into operation.

The decision by the government of Prime Minister Nouri al-Maliki to buy several old Russian Su-25 ground attack aircraft would not affect U.S. plans to deliver more advanced weaponry to Iraq, Warren said.

"We are very aware of the need Iraq has for advanced weapons,” Warren said. He said 400 of the promised 500 Hellfire missiles bought by Iraq had already arrived and the U.S. still intended to deliver F-16 fighters to Iraq in the fall.

The Iraqis said they were buying Russian equipment because U.S. deliveries were too slow. The Russian aircraft will arrive in three or four days, said Gen. Anwar Hama Ameen, commander of the Iraqi Air Force.

Over the weekend, a spokesman for the Islamic State of Iraq and the Levant (ISIL) said in online statements that the terror group was declaring a caliphate across Syria and Iraq. ISIL was now to be called the "Islamic State” and the ISIL leader, Abu Bakr al-Baghdadi, was to be known as "Caliph Ibrahim,” the spokesman said.

"Listen to your caliph and obey him. Support your state, which grows every day,” the spokesman said in the online statements.

The declaration of the Islamic state came as Maliki faced negotiations with parliament on forming a new government. The U.S. had demanded that the Iraqi government be more inclusive and give voice to the Shia, Sunni and Kurdish communities before possible airstrikes against the extremists would be considered.

At the Pentagon, Pentagon officials would neither confirm nor deny that the Bataan was the first ship to which terror suspect Ahmed Abu Khatallah was taken for interrogation following his capture in Benghazi in a Special Forces raid earlier this month.

Khatallah is considered a main suspect in the 2012 Benghazi attacks that killed Ambassador Christopher Stevens and three other Americans.

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