Far fewer unaccompanied immigrant children are crossing the Texas-Mexico border, allowing the federal government to close the temporary shelters that it hurriedly opened to handle the surge, authorities say.

The Department of Homeland Security released data Thursday showing that about 5,500 unaccompanied children were arrested in July, barely half the number in May and June and the fewest in a month since February. Similarly, arrests of parents with children dropped by more than half last month, to just over 7,400.

DHS Secretary Jeh Johnson welcomed the decline but said the current numbers are still much higher than in previous years.

“We continue to have much work to do to address this issue, and our message continues to be clear — ‘Our border is not open to illegal migration,’ ” Johnson said in a statement.

Arrests in South Texas have fallen in recent weeks to about 100 per day, down from 300 or more in June, according to the Border Patrol.

The decline could be the result of searing summer temperatures or a messaging campaign in both the U.S. and the migrants’ home countries that stresses the dangers of the journey and warns they will not be allowed to stay. The government has reduced the removal time for many adults traveling alone to about four days from 33, Johnson said. The unaccompanied children from Central America, however, are entitled under the law to a hearing to determine whether deporting them would put them in danger.

Officials on the border are careful not to suggest that the crisis has passed. When temperatures subside, they say, the children could be back in greater numbers.

The White House has shied away from taking credit for the decrease, which gives the administration more time to deal with the immigrants who have already arrived.

The slowdown also seems likely to reduce the urgency for Congress to act after adjourning last week without a deal to give President Barack Obama any of the money he has asked for to handle the influx.

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This week, the federal agency charged with housing the children announced it would soon suspend operations at three temporary shelters with a total of about 3,000 beds. Government officials said the existing network of federally contracted shelters would suffice, at least for now.

From October to July, 63,000 unaccompanied children entered the U.S. illegally, double the number from the same period a year earlier.

Total apprehensions — adults and juveniles — in the Rio Grande Valley were 24,500 in July. That was down from about 38,000 in June but still well above the 15,000 in July 2013, according to the Border Patrol.