WASHINGTON — The Pentagon, bearing the brunt of criticism for shortfalls in National Guard supplies in the wake of last week’s devastating tornado in Kansas, acknowledged yesterday that Army National Guard units currently had only 56% of their required equipment.

Defense Secretary Gates told a Senate hearing that current equipment levels are the lowest since the September 11, 2001, attacks. He said that the Bush administration’s current defense budget request, which asks for $22 billion for the Army National Guard over the next five years, would take guard units up to 76% of their authorized equipment levels.

“There’s no question that there’s been a drawdown of equipment in the National Guard,” Mr. Gates said, adding that even before September 11, guard units normally were equipped at about 75%. “Clearly, we need to follow through with this program to rebuild the stocks of equipment that are available to the National Guard.”

Mr. Gates faced pointed questions on guard readiness at a Capitol Hill hearing from a bipartisan group of senators, who argued that repeated deployments to Iraq were causing shortages in equipment needed for homeland security and national disaster response.

The issue moved back into the spotlight after Kansas’s Governor Sebelius, a Democrat, pointed to the shortfalls after a tornado flattened the farming town of Greensburg, Kan. Guard shortfalls delayed the state’s emergency response, she said.

President Bush visited the town on Wednesday as administration officials continued to insist that Ms. Sebelius had all the resources she needed to respond to the crisis. R. David Paulison, director of the Federal Emergency Management Agency, said he has been in repeated contact with the Army general in charge of Kansas’ guard units, who assured him the Army had what it needed.

“He said he has plenty of equipment for this disaster,” Mr. Paulison told reporters traveling with Mr. Bush to Kansas. “I’ve asked probably at least 20 times, ‘Is there anything that you need that you don’t have?’ The answer is no. And that’s from the governor, the general, the mayor, and the city manager.”

Ms. Sebelius reiterated the criticisms during Mr. Bush’s visit, however. She said the state has been able to muster the resources to deal with the Greensburg disaster, but would be hard pressed to meet any other contingencies.

“If we have another incident … that needs guard support, I will be in a situation where we have to choose what we do — and that’s a terrible choice to make,” she said. “After four years [of war] there’s no question that, year after year, guard supplies are depleted not just in Kansas but all over the country.”

White House and Pentagon officials have insisted that sharing agreements between the states would ensure that any shortfalls faced by one state during a disaster could be filled by neighboring states. But some experts have challenged that claim, noting that nearly every state is running short of equipment because of overseas deployments.

“These compacts are practically nullified now because all states have people in the sand box; I am talking about Iraq,” said Melvyn Montano, former head of the New Mexico National Guard. “If you have four or five states around you, where are they going go get their equipment from? Because they all have been deployed.”

The chorus was joined Wednesday by senators from several states, including Senator Domenici, a Republican of New Mexico, who told Mr. Gates that his state was facing severe shortages in the military infrastructure that supported its guard units.

The Army National Guard has told members of Congress that it had $23.6 billion in unfunded requirements that it would need to get back to 100% readiness. Senator Leahy, a Democrat of Vermont, said failure to fill those requirements means that some states only had 35% of their guard equipment.

Army National Guard requirements not funded by Mr. Bush’s budget include 18,600 Humvees, which would cost $2.4 billion over the next five years, and 30,100 trucks, which would require an additional $5.6 billion, according to an analysis cited by Mr. Leahy. It indicated the guard needs $6 billion for 159 Chinook helicopters, the most costly deficiency.