President Joe Biden visited the site of a 50-year-old Pittsburgh bridge that collapsed just hours before he arrived for a scheduled visit to the city on Friday, dramatically reflecting the bad condition of the country’s creaky infrastructure.

"The idea that we have been so far behind on infrastructure, for so many years — it's just mind-boggling," a Reuters report from Pittsburg cited Biden as saying.

According to a CNN report, four vehicles were on the bridge when it fell. Teams are still performing reconnaissance to ensure no one was under the bridge when it collapsed, he said.

First responders used ropes to rappel down 150 feet to get to the victims, Jones said. Crews also used what he called a "daisy chain" where they linked hands to reach the victims and pull them out.

One emergency worker described the scene after the collapse as loud as a jet engine. Biden praised the work of rescuers, noting a natural gas leak that was not stopped until some 30 minutes after first responders arrived at the scene.

Ten people are reported to have suffered minor injuries, including four who were taken to the hospital, city officials said. Jones added that crews would search under the bridge for any survivors.

Images of the collapse showed the four-lane span buckled into three large sections, with several vehicles piled in the rubble of the collapsed roadway at the bottom of the ravine. The tail end of a long, red city bus appeared trapped by the rubble.

The massive gas leak caused by the collapse forced the evacuation of several families from their homes before being brought under control, Jones said.

The collapse came just two weeks after Pennsylvania got $327 million from the U.S. Department of Transportation for bridge repair as part of the Biden administration's new infrastructure law.

Biden said he was astonished to learn Pittsburgh had more bridges than any city in the world. "And we're going to fix them all," he said before leaving the site.

According to the US Transport Department there are as many as 44,000 bridges in the country that are in poor condition, and over 3,000 of them are in Pennsylvania.

The cause of the collapse is under investigation, he said. The National Transportation Safety Board has a team on site and is bringing in a crash reconstructionist who will map the scene with a drone. Once the mapping is done, authorities will remove vehicles and debris from the scene.