PHOENIX — U.S. immigration officials overwhelmed by a flood of women and children from Central America who illegally crossed the border from Mexico are moving hundreds of unaccompanied boys and girls this weekend to a makeshift detention center in Nogales, Ariz.

The move is the latest effort by the Obama administration to cope with the tens of thousands of women and children from El Salvador, Guatemala and Honduras that it says have fled violence and poverty in their countries and have streamed into Texas in recent months.

Gov. Jan Brewer of Arizona, who has criticized President Obama for releasing some of these migrants at a bus station in Phoenix, said federal officials had told her office that the policy “will continue into the foreseeable future.”

Since Memorial Day, federal immigration officials have flown hundreds of women and children to Tucson, where they were given medical and other tests. They were then sent by bus to Phoenix and left at the Greyhound station to find their relatives around the nation. They were told to report to an immigration center within 15 days of reaching their destination, officials said.

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Immigration advocates have criticized the federal government for stranding the women and children in extreme heat with no money or food. Volunteers have stepped in to help them reach their families.

The government may continue to drop off women and children in Phoenix, but it has also opened a facility in Nogales to temporarily house children before they are sent to other holding centers. Brewer said 432 children were sent to Arizona on Friday and that an additional 734 were expected to arrive over the weekend.

“I am disturbed and outraged that President Obama’s administration continues to implement this dangerous and inhumane policy, meanwhile neglecting to answer crucial questions our citizens demand and deserve,” the governor, a Republican, said late Friday.

A spokesman for Brewer, Andrew Wilder, said Arizona officials were sending federal supplies to Nogales. The Associated Press reported that the shelter there was running out of essential materials, that children were sleeping on plastic cots and that portable toilets and showers had been taken to the center.

The warehouse in Nogales can hold about 1,500 people, Wilder said. The children will be vaccinated and given a medical checkup and then sent to shelters at military facilities in Oxnard, Calif.; San Antonio; and Fort Sill, in Lawton, Okla.

“This is a way-station, and they’re just coming through and shipping in and shipping out as soon as they can,” Wilder said. “We heard this facility was chosen because it was not being used and could be converted easily.”

Immigration and Customs Enforcement has only one facility for children, in Pennsylvania.

Since October, more than 47,000 children traveling without parents have been caught trying to cross the Southwest border, a 92 percent increase over the similar period a year earlier.

Federal officials predict that at least 60,000 minors will try to cross into the United States without their parents this fiscal year.