PHOENIX — Saying immigrant children being bused to Arizona may be being placed in danger, Maricopa County Attorney Bill Montgomery warned federal officials Monday they may be violating state child-abuse laws.

In a letter to a top immigration official, Montgomery said he fears some of the children being left at Tucson and Phoenix bus stations “without food, water or shelter, or means to acquire same” are not really traveling with a parent despite claims by Immigration and Customs Enforcement to the contrary.

And he cited an Arizona law that prohibits someone who has care or custody of a child from permitting them to be injured or placed in a dangerous situation.

He said that, given the 100-plus-degree temperatures, “any federal official who directly engages in such conduct or who authorizes such conduct may be guilty of a Class 4 felony.” And if that is classified as a dangerous offense, the presumptive prison term is six years behind bars.

Montgomery’s complaint came on the same day that White House officials said they had prepared for an increase in women and children from violence-prone Central American countries, but the flood of immigrants, coming primarily through the Rio Grande Valley in Texas, was larger than anticipated. Administration officials would speak with reporters only on background and not for direct attribution.

Those officials admitted that they’re not meeting a requirement in federal law to process unaccompanied minors within 72 hours and turn them over to federal health officials.

What that means is that the children brought to Arizona are remaining locked up for longer than they should at a refurbished warehouse at the Nogales Border Patrol station that lacks basic amenities, like indoor plumbing.

That point got the attention of U.S. Rep. Raúl Grijalva, D-Tucson, who sent a letter Monday to the White House.

“I understand resources are strained and immediate actions need to be taken,” Grijalva wrote the president. “However, according to reports, this facility is not in a suitable condition to hold the unaccompanied children.”

He wanted details of when improvement would be made “to make conditions habitable” or, if not, what the contingency plan is. One administration official said efforts are underway to provide hot meals and shower facilities, “all kinds of things to make their life there as comfortable as possible — but with the ultimate goal of trying to move the children as quickly as possible.”

That, however, creates another problem: Administration officials admit that the three facilities being prepared for the children at military bases in Texas, California and Oklahoma can house perhaps a maximum of 3,000. But hundreds have been arriving daily at Nogales for processing.

Administration officials said the Department of Health and Human Services, which is accepting legal responsibility for the unaccompanied minors, has access to thousands of other beds at existing facilities. But they said that clearly is not a good long-term answer.

What is, they said, is trying to find adult relatives for these children — even those in this country illegally and awaiting their own deportation proceedings — or at least foster-care families.

Immigration and Customs Enforcement is saying all unaccompanied minors who enter the country illegally are being sent first to a processing center at Nogales and eventually to more permanent housing at military bases, never being abandoned alone. But Montgomery said it appears they may be being mixed in with families who are simply being bused to Arizona.

Montgomery said he’s concerned that some adults are not really relatives of the children and that they can abandon them. And he said that makes ICE responsible for not verifying the familial relationship. Montgomery conceded, though, that he cannot do much at this point without hard proof.

ICE officials did not immediately respond to queries about the letter to Thomas Winkowski, principal deputy assistant secretary for ICE. But Montgomery said he would be skeptical of whatever the agency says.

In their background briefing, the administration officials brushed aside questions about whether the sudden rush of immigrants is due to a belief that the Obama administration will give them amnesty if they get here.

They pointed out that the Deferred Action for Childhood Arrivals program implemented two years ago specifically applies to those already here on that date. And they said nothing in congressional legislation to provide some relief to those in the country would apply to these new arrivals.

Instead, they said the problem appears to be a direct outgrowth of violence in Central America.

“Honduras has the highest murder rate in the world,” one official said, with Guatemala and El Salvador not far behind.

She said if children were being lured in anticipation of a new amnesty, then there would be an across-the-board increase in migrants from all countries. But she said that is not the case.

Numbers provided by Border Patrol show that the number of unaccompanied children from Honduras is nearly double the same time a year ago. There also are large increases from El Salvador and Guatemala.

Yet the number of unaccompanied minors from Mexico actually is about a third less. And most of that is coming through the Rio Grande Valley, where numbers more than doubled. By contrast, the increase through the Yuma sector is only 34 percent, with a 5 percent decline in the Tucson sector.