WASHINGTON (AP) — Hundreds of U.S. troops have arrived in Haiti, and a high-ranking Army officer said Friday that food, water, medicine and other emergency relief supplies are being rushed to victims of this week’s massive earthquake.

Lt. Gen. Ken Keen, appearing on nationally broadcast morning news shows, reported from Haiti that some 300 members of the Army’s 82nd Airborne Division arrived overnight, as well as sailors coming in aboard the aircraft carrier USS Carl Vinson.

“We have much more support on the way,” Keen said. “Our priority is getting relief out to the needy people, to mitigate the suffering that the Haitian people are experiencing right now.”

It was the first major influx of troops from the United States, which has taken the lead in world efforts to assist the devastated country.

The infusion of troops began as President Barack Obama declared himself determined to carry out a wide-ranging rescue despite the strain that such a vast undertaking invariably would take.

“To the people of Haiti, we say clearly and with conviction, you will not be forsaken,” Obama said Thursday. “You will not be forgotten. In this, your hour of greatest need, America stands with you.”

Military personnel began trickling into Haiti on Wednesday to restore operations at the airport and join the relief effort. An early assessment team has outlined an urgent requirement for helicopters to ferry supplies and victims, as well as equipment to purify water and clear road debris.

A primary challenge is the badly damaged seaport that will make it difficult for ships — carrying the kinds of mass amounts of supplies and helicopters needed in a natural disaster — to offload their equipment. Likewise, the small airport at Port-au-Prince was described as congested and chaotic with civilian flights canceled and planes stranded without the ability to refuel.

As many as 3,500 troops from the 82nd Airborne Division’s 2nd Brigade were expected by Monday with some 2,200 Marines also en route. The Norfolk, Va.-based USS Carl Vinson was expected to bring some 19 helicopters.

The State Department confirmed the death of one American, career diplomat Victoria DeLong, a cultural affairs officer at the U.S. Embassy who was killed when her home collapsed. Spokesman P.J. Crowley said three other Americans were known to be missing and the embassy had made contact with nearly 1,000 U.S. citizens in Haiti, a fraction of the estimated 45,000 there.

Aware of the steep political cost that George W. Bush paid for an ineffective response to Hurricane Katrina, the White House has labored to show Obama has been intensely engaged since immediately after the quake struck. Details of evening Situation Room meetings, phone calls with world leaders and canceled events were being released almost hourly.

Obama himself warned it would take hours “and in many cases days” to get the full U.S. contingent to Haiti.

“None of this will seem quick enough if you have a loved one who’s trapped, if you’re sleeping on the streets, if you can’t feed your children,” Obama said at the White House, his second appearance on the topic in as many days, followed by a third later in the day. “So today, you must know that help is arriving. Much, much more help is on the way.”

The Federal Aviation Administration halted all civilian aid flights to Haiti, though not government ones, for about eight hours on Thursday. The Haitian government said there was no more room on ramps for planes to unload their cargo, and some planes on the ground didn’t have enough fuel to leave.

Keen was interviewed on ABC’s “Good Morning America.”