(CNN) - US Border Patrol apprehensions along the southern border dropped in June for the first month since January, according to preliminary internal data obtained by CNN.
There were nearly 95,000 apprehensions on the US-Mexico border last month, down about 28% from 132,887 in May -- the highest month in more than a decade. Despite the drop, this June was much higher than the same time last year, when there were 34,089 apprehensions.
The numbers are in line with forecasts from acting Homeland Security Secretary Kevin McAleenan, who said Friday that it appeared there would be a 25% decrease in June numbers of migrants crossing at the US-Mexico border.
A dip in border crossings is common during the hot summer months, though McAleenan downplayed the role of seasonal trends in migration, saying that he expects to be able to tell by late July if initiatives undertaken by the US and Mexico governments will have a sustained impact.
Customs and Border Protection does not comment on unofficial numbers, according to a spokesperson. The agency generally releases final monthly numbers towards the beginning of the subsequent month.
Last week, McAleenan credited Trump administration initiatives for the drop, especially the increase in interdictions by Mexico over the past three weeks and the return of some asylum seekers to Mexico for the duration of their immigration proceedings.
On June 8, in the wake of a tariff treat from President Donald Trump, the US and Mexico signed a deal, which included an agreement by Mexico to take "unprecedented steps" to increase enforcement and curb irregular migration.
Border Patrol officials in the Rio Grande Valley of Texas last week said Mexico's efforts were having an effect on the numbers, but were skeptical it would have lasting impact, citing previous initiatives carried out by the Mexican government.
The numbers come amid public outcry over reports that migrant children were held under poor health and hygiene conditions at multiple Border Patrol locations in Texas. On Monday, members of Congress toured facilities in the El Paso region, as demonstrators and counter-demonstrators clashed outside. Many of the Democratic congressional members expressed outrage over the conditions they witnessed.
The demographic shift -- from single adults from Mexico to families and children predominantly from Northern Triangle countries of Guatemala, Honduras and El Salvador -- as well as the large influx of migrants arriving over the past year, has strained facilities along the border, stretched CBP resources thin and caused low morale among agents.
CNN's Priscilla Alvarez contributed to this report.
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