Six F-15E Strike Eagle jets arrived at Incirlik Air Base in Turkey on Thursday, joining other U.S. manned and unmanned aircraft already stationed there to prosecute the campaign of air strikes against Islamic State (ISIL) militants in Iraq and Syria.

The Boeing [BA] F-15Es are assigned to the 48th Fighter Wing based at the Royal Air Force base at Lakenheath in the United Kingdom. The twin-engine, two-seater E-model F-15s will add significant air-to-ground heft to the fleet of aircraft the United States and coalition allies have assembled to bomb ISIL targets.

Air Force A-10 Thunderbolts have been providing close air support for Iraqi and Kurdish troops and Syrian rebel groups fighting ISIL. Navy F/A-18 Hornets, also built by Boeing, and Air Force F-22 Raptors, made by Lockheed Martin [LMT], have also delivered ordnance during the campaign but Pentagon officials have been reluctant to say which platforms are conducting which strikes. At least six single-seat F-15Cs are based at Incirlik to perform air patrols of Turkish airspace.

A Sniper ATP on a U.S. Air Force F-15. Photo: U.S. Air Force.
A Sniper ATP on a U.S. Air Force F-15. Photo: U.S. Air Force.

The F-15 is a dual-role fighter that can handle both air-to-air engagements against enemy aircraft but is also equipped with high-tech targeting sensors and avionics that allow it to accurately strike ground targets. It carries a Raytheon [RTN] APG-70 radar that allows for detection of ground targets at long ranges and a terrain following radar that allows the pilot to safely fly at very low altitudes.

Near the ground, it can deploy the low-altitude navigation and targeting infrared for night, or Lockheed Martin LANTIRN, system which allows low-level flight at night and in all weather conditions and deploy various precision-guided and gravity bombs.

The F-15E can carry most weapons in the Air Force arsenal and sports an integrated 20mm cannon with 500 rounds.

The jets arrived at the outset of a major offensive led by Kurdish Peshmerga fighters against ISIL in Sinjar, Iraq. In the past 24 hours, U.S. aircraft have conducted at least 36 airstrikes on a highway that serves as a key supply route for ISIL between its declared capital in Raqqa and Mosul.

“Peshmerga forces with the support of the coalition air campaign and coalition advisers are attempting to sever ISIL’s primary line of communication,” Pentagon spokesman Peter Cook said in a press conference Thursday. “The targeting of highway 47 over Sinjar Mountain and the ground operation by the Peshmerga will degrade the ability of ISIL terrorists to funnel fighters and equipment into Iraq and help cut off an important means of funding terrorist activities.”

U.S. personnel are on the ground supporting the Iraqi Kurdish forces in their ground offensive by helping to designate viable targets for coalition air strikes, Cook said. He called it a collaborative effort between U.S. and Kurdish forces with Kurds in the lead and stressed that U.S. personnel were not acting as joint tactical air controllers (JTACs), which would require U.S. troops to be on the front lines in direct contact with aircraft overhead.

Critics of the Obama administration’s plan to destroy ISIL, including senior lawmakers on both the House and Senate armed services committees, have insisted that JTACs need to accompany Iraqi forces into battle to more accurately designate viable targets.