Washington(CNN) The Department of Homeland Security inspector general reiterated Monday that it's still concerned about conditions at border facilities.

Over recent months, DHS officials warned of worsening conditions at the southern border amid a dramatic spike of apprehensions. Images included in internal watchdog reports, as well as anecdotes of migrants in standing-room only conditions, among others, brought those warnings to the forefront.

"We understand that the department is facing a difficult challenge; however, the department has not developed a long-term plan to address the issues within detention centers along the southern border," reads assistant IG for Special Reviews and Evaluations Diana R. Shaw's testimony, which was posted ahead of a House Judiciary subcommittee hearing on detention at Customs and Border Protection facilities.

"The steps the department has taken to implement our recommendation to alleviate dangerous overcrowding continue to fall short," it continues.

The DHS IG also shared its concerns on Twitter Friday.

The hearing follows a series of internal watchdog reports describing perilous conditions at facilities along the US-Mexico border. Vice President Mike Pence saw the overcrowded conditions facing migrant adults and children in CBP custody firsthand on Friday, becoming the highest-ranking member of the Trump administration to visit two federal detention centers in Texas.

"To be honest with you, I was not surprised by what we saw," Pence told reporters Friday, citing the humanitarian crisis and congestion. "This crisis is real, the time for action is now."

In May, the DHS IG found "dangerous overcrowding," and unsanitary conditions at an El Paso Border Patrol region processing facility, following an unannounced inspection.

The IG found "standing room only conditions" at the El Paso Del Norte Processing Center, which has a maximum capacity of 125 migrants. On May 7 and 8, logs indicated that there were "approximately 750 and 900 detainees, respectively."

"We also observed detainees standing on toilets in the cells to make room and gain breathing space, thus limiting access to the toilets," the report, which was first obtained by CNN, stated.

And in July, the DHS IG reported extreme overcrowding and children younger than 7 being held in custody for more than two weeks -- far longer than the allowed 72 hours -- at Border Patrol facilities.

The unannounced inspections took place in early June in the Rio Grande Valley region of Texas, along the US-Mexico border -- the busiest sector for arrests on the southern border.

In her testimony, Shaw acknowledges the DHS responses to the reports and plans to alleviate the issues raised, but notes that, in some cases, it's insufficient. In response to the July report, for example, DHS resolved to add tents capable of holding hundreds of people.

"Again, while additional tents may reduce overcrowding, we remain concerned that DHS is not taking sufficient measures to address prolonged detention in CBP custody among single adults," the testimony reads.

The inspector general's office is also investigating efforts to reunify children with separated families, CBP's processing of asylum seekers, the holding of detainees over the allowed 72 hours, and the use of fiscal year 2019 appropriated funds for humanitarian assistance.