Defense Secretary Ash Carter said Wednesday the U.S. is willing to assist the Iraqi army with more personnel and attack helicopters to help it fight Islamic State militants, especially in the battle to retake a key city in Iraq.

In recent days, Iraqi forces advanced on Ramadi, the provincial capital of Anbar province, retaking a military operations center and a neighborhood on the outskirts of the city. IS fighters captured Ramadi in May in a major setback for Iraqi troops.

“The United States is prepared to assist the Iraqi army with additional unique capabilities to help them finish the job, including attack helicopters and accompanying advisers” if circumstances dictate the extra assistance and if requested by Prime Minister Haider al-Abadi, Carter said.

Carter outlined the steps as the administration faces criticism from Congress about its strategy to defeat the IS militants, reflecting a nation’s growing fears about the threat of terrorism.

Carter said that during the past several months, the U.S.-led coalition fighting IS in Iraq and Syria has provided specialized training and equipment, including combat engineering assistance such as bulldozing, and munitions such as AT-4 shoulder-fired missiles to stop truck bombs, to the Iraqi army and counter-terrorism service units entering Ramadi neighborhoods from multiple directions.

He predicted tough fighting ahead, but said the Iraqi forces have shown resilience when faced with counter-attacks from IS.

It was the first time that Carter has testified before the committee since IS claimed responsibility for bombing a Russian airliner and attacks in Beirut and Paris and the deadly attack in San Bernardino, California, by a self-radicalized couple.

Sen. John McCain, R-Ariz., chairman of the committee, advocated for more U.S. troops to be sent to stem IS momentum. “There are 20,000 to 30,000 of them. They are not giants. Somebody is going to have to convince me that air power alone” is going to do the job, McCain said.

(AP)