WASHINGTON (AP) – The Army says around 2,600 soldiers from a combat aviation unit will go to Iraq ahead of schedule, part of the support troops the Defense Department says are needed.

With their assault and transport helicopters, the extra brigade can help with attack and reconnaissance missions, air assaults and raids and medical evacuations in support of combat troops already flowing in for the President George W. Bush’s buildup of forces in Baghdad and Iraq’s western Anbar province.

The Army’s 3rd Infantry Division combat aviation brigade will go to Iraq 45 days earlier than planned, the Army said in a statement. That means the troops, the 3rd Combat Aviation Brigade, will go at the beginning of May.

Officials said Gen. David Petraeus, the new U.S. commander in Iraq, requested the air support, and he wanted the buildup to move as quickly as possible. “This was requested over a month ago as part of the surge,” said Col. Steven Boylan, public affairs officer for Petraeus. “These are what we call the enablers.” Two months ago, Bush ordered 21,500 additional American troops to Iraq to help calm the violence in Baghdad and Anbar. He did not initially mention that support units also would be needed. Officials later said the number of support troops necessary for the influx could be around 7,000.

Besides the aviation unit, 2,400 combat support troops and 2,200 military police would help with an anticipated increase in detainees picked up during the crackdown. That means a total buildup of roughly 30,000 to ride herd on rising sectarian violence and insurgents, said a Defense Department official, who spoke on condition of anonymity because he was not authorized to speak on the record.

Asked what he would tell critics of the steady additions to the original number, the official said some requests came after Petraeus arrived in Iraq and assessed what he needed. He said Defense Secretary Robert Gates wants to give commanders what they believe they need to do the job as long as the requests are justified.

In an AP Radio interview, Canadian Army Maj. Gen. Peter Devlin, deputy commanding general of coalition forces in Iraq, said of the extra troops, “What was always asked for was, beyond the combat formation, were the typical enablers that go along with combat formations.” Asked whether there are likely to be more such requests, he said, “Yes. It is exactly something that you would expect, in that there is a need for support troops to do what they do.”

Roughly 142,000 U.S. troops now are in Iraq. About 60,000 are combat forces, the rest support troops. A few days early, the White House marked the coming fourth anniversary of the U.S.-led invasion of Iraq on March 19-20, 2003. A fact sheet was headlined: “Four years later: new strategy requires patience and determination.”

“On the fourth anniversary of the beginning of Operation Iraqi Freedom, the regime of a brutal dictator has been replaced by a democratically elected government operating under one of the most progressive constitutions in the Arab world,” the White House document said. “While there is much work to be done, there are encouraging signs of progress.”