A shipment of infant formula intended to fill a nationwide shortage arrived in the United States from Europe on Sunday, and a second flight was expected to bring additional supplies in the coming days, the Biden administration said.

The shipment, equivalent to about 500,000 eight-ounce bottles, contained a hypoallergenic formula for children with cow’s milk protein allergy, the White House said in a statement. It provides enough formula to take care of 9,000 babies and 18,000 toddlers for a week, Tom Vilsack, the agriculture secretary, said in televised remarks at the airport in Indianapolis, where the shipment arrived on a military plane from Ramstein Air Base in Germany.

“This shipment of formula serves a critical medical purpose and will help infants with specific dietary needs requiring specialized formula,” Mr. Vilsack said on Twitter.

A second shipment, which is expected to arrive this week, would bring the supply of formula up to the equivalent of 1.5 million eight-ounce bottles of three formulas, which would later be distributed from a Nestlé facility in Pennsylvania.

The transports are part of a series of measures taken by the Biden administration to address the shortage of infant and toddler formula that had threatened to become a political and public health disaster, as frustrated families searched depleted supermarket shelves.

President Biden invoked the Defense Production Act last week to increase production and authorized the use of Defense Department planes for “Operation Fly Formula” to respond to the crisis.

In February, Abbott Nutrition, which controls 48 percent of the formula market in the United States, voluntarily recalled some of its most popular brands — Similac, Alimentum and EleCare — after four babies were hospitalized with bacterial infections. At least two babies died, although the company said this month that there was no evidence its formula caused any known infant illnesses.

Abbott also shut down its plant in Sturgis, Mich., and the Food and Drug Administration warned consumers not to use the recalled brands that were produced there.

The effects of the closure of the Sturgis plant have been widespread, with stores limiting purchases of formula and parents desperately seeking supplies or trying to make formula at home, which pediatricians discourage. The shortage has also been exacerbated by supply-chain woes and labor shortages associated with the pandemic.

The statement from the White House said the pallets of formula that arrived on Sunday were “prioritized because they serve a critical medical purpose” and were in short supply because of the plant closure in Sturgis.

In another step to address the acute shortages, the F.D.A. announced last week that it would relax some of its regulations to encourage new suppliers to provide formula. The United States normally produces about 98 percent of the formula it consumes, with imports coming primarily from Mexico, Ireland and the Netherlands.