Islamic State Kills U.S. Navy SEAL in Northern Iraq

U.S. Navy SEALS are briefed before a night mission to capture Iraqi insurgent leaders near Fallujah, Iraq, July 27, 2007. John Moore/Getty

The Islamic State militant group (ISIS) killed a U.S. Navy SEAL in northern Iraq on Tuesday after blasting through Kurdish defences and overrunning a town in the biggest offensive in the area for months, officials said.

The special warfare operator was named as Charlie Keating, aged 31, from the state of Arizona.

The serviceman was the third American to be killed in direct combat since a U.S.-led coalition launched a campaign in 2014 to "degrade and destroy" Islamic State and is a measure of its deepening involvement in the conflict.

"It is a combat death, of course, and a very sad loss," said the U.S. Defense Secretary, Ash Carter.

The SEALs are considered to be among the most able U.S. special operations forces and capable of taking on dangerous missions. The serviceman's identity and rank were not disclosed by the Pentagon.

The governor of the U.S. state of Arizona, Doug Ducey, identified the serviceman as Navy SEAL Charlie Keating, and said Keating had attended high school in Phoenix.

"His death is a tragic reminder of the daily sacrifices made by our men and women in uniform—fighting evil and extremism on the front lines to protect freedom and democracy at home and throughout the world," Ducey said on his website.

The San Diego Union-Tribune newspaper, in southern California, cited unnamed SEALs and their family members in reporting that Keating was the grandson of Charles Keating Jr., a banker who played a leading role in the U.S. savings and loan scandal of the 1980s that embroiled five U.S. senators.

The newspaper reported Keating was engaged to a woman in Coronado, and the couple had planned to wed in November.

A senior official within the Kurdish Peshmerga forces facing ISIS in northern Iraq said the man had been killed near the town of Tel Asqof, around 28 kilometres (17 miles) from the militant stronghold of Mosul.

ISIS insurgents occupied the town at dawn on Tuesday but were driven out later in the day by the Peshmerga. A U.S. military official said the coalition had helped the Peshmerga by conducting more than 20 air strikes with F-15 jets and drones.

Although Iraqi pro-government forces have gradually pushed back ISIS with the help of US-led coalition air-strikes and military advisers, the jihadist group still controls large parts of the country's north and west.

There are more than 5,500 U.S. military personnel in Iraq. Some 3,870 are deployed to advise and assist local forces fighting ISIS militants.

The remainder includes special operations personnel, logistics workers and troops on temporary rotations.

Last month, the U.S. announced that it planned to send 200 additional advisers to Iraq by the end of the year and deploy them closer to the frontlines so that they could assist in the operation to retake Mosul.

In March, U.S. Marine Staff Sergeant Louis Cardin was killed in a rocket attack by ISIS while providing force protection fire support at a coalition firebase near Makhmour, south-west of Mosul, that had only become operational a few days earlier.

U.S. Army Master Sergeant Joshua Wheeler died in October during a special forces mission to rescue hostages held at an ISIS prison near Hawija, west of Kirkuk.