Chairman of the Joint Chiefs of Staff Gen. Martin E. Dempsey talks with servicemembers deployed to Iraq during a town hall in Baghdad, Iraq, on July 18, 2015.

BAGHDAD (Tribune News Service) — An Iraqi military operation to retake the key Sunni city of Ramadi from Islamic State militants is gaining momentum, the top U.S. military officer said Saturday.

Gen. Martin Dempsey, chairman of the joint chiefs of staff, said his senior field commanders here do not require additional U.S. forces or the need to deploy advisers in the field with Iraq's combat forces for the offensive to succeed.

"I asked the senior leaders point blank: 'Are we at the point where, in order to make sure this mission succeeds, that we need to be here in greater numbers and go farther forward?'" Dempsey told reporters as he wrapped up a daylong visit here. "And the answer was 'no'."

Iraqi forces have been repeatedly humiliated in battles by the vastly smaller ranks of Islamic State fighters. That has prompted critics of the administration's limited presence in Iraq to push for more U.S. forces in Iraq, including teams that could accompany Iraqi combat forces to help call in more precise airstrikes against the militants.

Sen. Lindsey Graham, a Republican presidential candidate, has suggested a force of 10,000 U.S. troops to speed up the training of Iraqi troops.

Currently, there are about 3,500 U.S. troops in Iraq. Their primary role is to train and support Iraq's military so they can lead the fight and keep American soldiers out of combat. Dempsey said he supports that policy.

U.S. forces have trained 9,700 Iraqi forces so far.

The Islamic State, which has taken over large areas of Iraq in the past year, remains a lethal enemy. An attack in a crowded marketplace in Diyala Province east of Baghdad on Friday night killed at least 115 people, primarily Shiites.

The militants attacked a gathering marking the end of the holy month of Ramadan, which ended for Shiites Friday.

The Islamic State, composed of Sunni Muslims, has tried to spark sectarian warfare with Shiite Muslims, who dominate Iraq.

The collapse of Ramadi in May was a blow to Iraq's military, which abandoned the city without much of a fight.

Last Monday, Iraq's government announced an offensive to take the city back. Iraq's military has not yet begun an assault into the center of the city, where an estimated 250 to 300 militants are holed up. Instead, it is trying to surround the city before closing in on the militants.

Brig. Gen. Yahea Resool, a Defense Ministry spokesman, said Iraq's forces have had initial successes in securing areas on Ramadi's outskirts.

Iraqi forces are also attempting to isolate Fallujah , a Sunni city east of Ramadi, to cut off the flow of fighters and arms between the two Anbar Province locations.

The Iraqi government has assembled a force of about 10,000 troops who include Iraqi army, national police, Shiite militias and Sunni tribal forces.

Resool defended the slowly moving operation, saying it will help protect civilians and minimize destruction of the city. "We are not in a hurry," Resool said. "We have to protect the people and the infrastructure."

The U.S. led coalition has supported the offensive with airstrikes, but coalition officials acknowledge that stringent rules designed to avoid civilian casualties can slow the process of ensuring that militants are targeted.

"We have very strict guidelines in terms of what we can and cannot do," said Brigadier James Learmont, a coalition official from Britain. Airstrikes require the approval of senior officers before they are approved, he said.

The offensive also had been slowed by the Iraqi government's initial reluctance to provide support for Sunni tribal fighters in Ramadi who oppose the Islamic State's brutal tactics.

Iraqi Prime Minister Haider al-Abadi has had to contend with powerful Shiite politicians who prefer using Shiite militias rather than Sunni tribal forces for the Ramadi offensive.

"There is a competition within the government of Iraq on which security force will be the dominant force," Dempsey said.

He said the government has resolved many of those issues and support is beginning to flow to the Sunni tribes.

