Defense Secretary Ash Carter traveled to Iraq Wednesday on an unannounced war zone visit to find new ways to hasten the destruction of the Islamic State (ISIS) group.

Carter is planning to meet with his commanders and with Iraqi leaders, as he looks for ways to broaden the U.S. assistance to Iraq, including what will likely be discussions about America's willingness to send attack helicopters and more troops into the fight.

Because weather problems were restricting some air travel around Baghdad, it was uncertain which Iraqi leaders Carter would be able to see.

The focus in recent days has been the battle in Ramadi, the provincial capital of Anbar province, which was taken by ISIS militants earlier this year. Iraqi forces have been preparing to try to take the city back, encircling it. But progress has been slow.

Carter has been saying he wants to identify new ways that other coalition members can contribute to the campaign. One goal is to get allies to take on some of the missions being done by some of the approximately 3,500 U.S. troops in Iraq, so that those forces can take on more specialized roles.

Carter is likely to talk to commanders and Iraqis about the new U.S. plan to deploy a new special commando force to Iraq. It would be designed to better capitalize on intelligence in order to target, capture and kill ISIS leaders. Called an "expeditionary targeting force," the special operations troops would be used to increase the pressure on the insurgents.

But details of the plan have not been disclosed, and U.S. officials haven't said when they may deploy to Iraq.

The Pentagon has also offered to send Apache helicopters to help the fight in Ramadi if Iraqi leaders request the aid. So far they have not.

Speaking to reporters traveling with him, Carter said the U.S. wants to use the Apache helicopters when they can "make a distinctive difference and have a strategic effect." He said he plans to discuss the offer with Iraqi leaders, adding that Prime Minister Haider al-Abadi has said he is willing to consider it and any decision is up to the Iraqi government.

A senior U.S. official said the U.S. has been making preparations and will be ready at any moment to dispatch the Apaches when requested. The official was not authorized to discuss the matter publicly, so spoke on condition of anonymity.

Carter's trip had been planned for some time, but on Monday during a visit to the Pentagon, President Barack Obama vowed to accelerate the campaign against ISIS, lending more urgency to the visit.

During a trip to Iraq in October, Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, called for better cooperation between all the Iraqi military factions so they can better coordinate with the U.S.-led coalition. The Iraqi security forces, the Kurdish government forces known as the Peshmerga, the Sunni tribes and the popular mobilization troops are at times at odds as they try to battle ISIS.