"And while we hear some Democrats in Washington, D.C., referring to U.S. Customs and Border facilities as 'concentration camps, ' what we saw today was a facility that is providing care that every American would be proud of", Pence said.
Pence said it was heartbreaking to hear from children who had walked two or three months to come to America and cross the border illegally, but he ultimately blamed Congress for failing to pass legislation that would deal with the influx of migrants at the southern border.
Central American families fleeing violence, poverty and drought have been coming to the U.S.in record numbers this year, peaking in May, when the Border Patrol made almost 133,000 apprehensions.
Pence said the centre at McAllen was a "prime example" of why the United States must secure its borders.
The cages were so crowded, according to the reporter, that it would have been impossible for all the men to lie down at the same time.
Speaking in front of the crowd, one protester said, "And these children no longer have the opportunity to dream the American dream, which is the one that they had or their families had".
"I knew we'd see a system that was overwhelmed". Lindsey Graham said he doesn't want to see migrant families being released from Border Patrol custody. "Stench was overwhelming. [Customs and Border Protection] said they were fed regularly, could brush daily [and] recently got access to shower (many hadn't for 10-20 days)".
Some Democrats have described the detention centers as "concentration camps" and say the US government is holding children in "cages". But he conceded that numerous men had not showered for 10 or 20 days because the facility previously didn't have showers.
As if in counterpoint to Democrats' testimony, Pence and eight GOP lawmakers toured a border station in Donna, Texas, a vast collection of air-conditioned, interconnected tents built in May to temporarily handle 1,000 migrants and now holding 800.
Earlier in his tour, Pence visited another detention facility.
Independent investigators for the U.S. Department of Homeland Security visited Border Patrol facilities in western Texas in May and found dozens of migrants packed into spaces so tight that some had to stand on toilets.
Pence said he had read the report, but added, "I can't account for that", when pressed by CNN about images of conditions similar to those of the McAllen facilities for families with children featured in the DHS inspector general's report.
A reporter traveling with Pence described seeing detainees lying on kindergarten-like napping mats on the floor, covered with a thin tinfoil-like blanket. The facility closed in January, but USA officials said a new facility is going on the same site to house as many as 2,500 adult migrants.
Health and Human Services officials say their youth holding facility in Carrizo Springs, Tex., aims to move children out of border patrol custody swiftly.
Numerous families there were to be released within 72 hours.
Pence and second lady Karen Pence approached a couple of boys sitting on a bench.