Updated

Recovery efforts in the collapse of a Minnesota bridge continued Friday under difficult conditions, with the death toll rising to five but the number of those still missing dropping from earlier estimates to only eight.

Murky waters and rapid currents made the search for those still unaccounted for dangerous and challenging, though the sheriff said it was going better than anticipated.

"This morning’s activity has gone much better than expected in terms of recovery operations," said Hennepin County Sheriff Rich Stanek at an afternoon news conference.

Click here to see uReport photos from FOX News viewers.

Click here to read about victims of the Minneapolis bridge collapse.

He said 20 divers were on the scene working in teams of three, with one in the water at a time and the other two providing backup. The morning operation took place along the east bank of the river, but the afternoon effort focused on the west bank, where five targets — possible vehicles — had been identified with sonar, according to the sheriff. Divers were wearing rubber gloves and trying to determine license plate numbers with their hands.

At least five people were killed and 100 injured when the Interstate 35W bridge plummeted more than 60 feet into the Mississippi River during Wednesday's rush hour. As many as 30 had been feared missing.

At least five of the injured were in critical condition, hospital officials said.

"We were surprised that we didn't have more people seriously injured and killed," Minneapolis Fire Chief Jim Clack told The Associated Press. "I think it was something of a miracle."

Searchers cleared four of the five submerged vehicles they'd identified and didn't find any victims, according to Stanek. The fifth vehicle had been crushed by another car and was lodged under it at the bottom of the river. The sheriff said it would have to be examined later using "heavy equipment."

"There are windows down in some of the cars which allows people to get out. We are going to go under the assumption that there are still people there no matter what," said Hennepin County Capt. Bill Chandler.

Crews focused on 13 areas on the upstream side of the collapse, said Stanek.

The search efforts continued even as authorities reviewed the safety record of the bridge, which had been designated "structurally deficient" as early as 1990.

The National Transportation Safety Board (NTSB) held a briefing about the disaster Friday afternoon, and said that investigators were looking in particular at the southern end of the bridge.

One person who had been feared missing turned up safe at work, but Stanek cautioned that finding the missing could be a slow process because of the scene.

"It's a terrible mess, quite honestly," he said. "We don't know how many cars were up on the bridge when it collapsed, we don't know how many victims were inside."

Search conditions were improving after the Army Corps of Engineers lowered the water by about two feet, officials said. But visibility continued to be a problem, and divers couldn't see more than 6 inches in front of them, Chandler said.

Earlier Friday, Stanek spoke of the tricky elements divers would have to contend with when they were conducting their search.

"We've got the current and debris, which create manmade whirlpools," Stanek said Friday morning. "Conditions are worse than yesterday."

More bodies had been spotted in the fast-moving currents, which were "even more treacherous" Friday than a day earlier, Stanek said. But the death toll, while expected to grow, was not expected to reach the numbers that the disaster amid bumper-to-bumper, two-lane traffic might have produced.

First Lady Laura Bush visited the scene Friday morning. During a tour of the disaster site, she praised the rescuers who rushed to the bridge in the chaos after the collapse. "There's so many good stories," Bush said of the response. It "lifts people and it really encourages people."

At a local American Red Cross chapter, she shook hands with Jay Reeves, the group's public safety coordinator, who helped evacuate children from a school bus.

"She said she appreciated the service that I provided. She believes it was lucky someone like me was right there on the spot," Reeves, 39, said, his voice breaking. "You'll have to excuse me, but that was pretty cool."

President Bush plans to travel to the site Saturday.

Firefighters pulled the fifth victim, the driver of a tractor-trailer rig that was engulfed in flames immediately after the collapse, from the wreckage late Thursday, fire department spokeswoman Kristi Rollwagen said. Video of the fire was among the most compelling images show in the immediate aftermath of the collapse.

The medical examiner's office was working to confirm the man's identity, but Rollwagen said firefighters didn't want the man's family to see the truck "over and over" on TV knowing he was inside.

Fourteen people were still at Hennepin County Medical Center, where most of the victims were taken, with five of them still in critical condition, spokeswoman Kathy Roberts said Friday.

The eight-lane I-35W bridge, which carried 141,000 vehicles a day, was in the midst of mostly resurfacing repairs when it buckled during the Wednesday evening rush hour.

Dozens of cars plunged into the river, some falling on top of one another. A school bus sat on the angled concrete near the tractor-trailer.

Among the missing is Sadiya Sahal, 23, and her 2-year-old daughter, Hanah Mohamed. Sahal, who is five months pregnant, left home at 5:15 p.m. with the toddler in the back seat. She called her family at 5:30 p.m. saying she was stuck in traffic on the bridge, according to Omar Jamal, a spokesman for the family. That was her last phone call.

"Her husband is destroyed. He's in shock," Jamal said.

Officials identified the dead as Sherry Engebretsen, 60, of suburban Shoreview; Julia Blackhawk, 32, of Savage; Patrick Holmes, 36, of Moundsview; and Artemio Trinidad-Mena, 29, of Minneapolis.

Ronald Engebretsen said he and his family were trying to come to grips with his wife's death. "She's a great person. She's a person of great conviction, great integrity, great honesty and great faith in her God," he said.

Shanna Hanson, a fire captain shown on video searching cars in the water shortly after the collapse, plunged into the water with no gear save a rope around her waist. She downplayed her efforts but described the conditions as extremely hazardous.

"Because the ground was so uneven because of the slabs and debris under there, the water depth kept changing, so that would change things up a bit. The visibility was really bad. It's the Mississippi and it's August, so visibility was under a foot," she told CNN.

"You have the jagged metal and broken glass, and the problem is you can't see what's around you and you don't know what else you're going to bump into," she added.

NTSB chairman Mark Rosenker said his investigators got two big breaks Thursday with a surveillance video showing the collapse and a computer program that would analyze how the bridge failed. Those two things would speed their work and allow them to do a smaller reconstruction of part of the bridge span, rather than the whole thing.

Despite the powerful images of devastation from the collapse, some believed the design of the bridge reduced the death toll.

Joseph Schofer, professor of civil and environmental engineering at Northwestern University, said the bridge's underlying arch truss stopped heavy pieces of steel from falling onto vehicles when the cars plunged into the water.

Gov. Tim Pawlenty responded Thursday by ordering an immediate inspection of all bridges in the state with similar designs, but said the state was never warned that the I-35W bridge needed to be closed or immediately repaired.

"There was a view that the bridge was ultimately and eventually going to need to be replaced," he said.

More than 70,000 bridges across the country are rated structurally deficient like the I-35W bridge, and engineers estimate repairing them all would take at least a generation and cost more than $188 billion.

"I think anybody who looks at the national picture, the national statistics and says that we don't have a problem would be naive or misleading the situation," Pawlenty said. "We have a major problem."

Authorities cautioned not to read too much into the "structurally deficient" tag. The designation means some portions of the bridge needed to be scheduled for repair or replacement. It wasn't a candidate for replacement until 2020.

The collapsed bridge is one of 1,160 bridges in that category, which amounts to 8 percent of bridges in the state. Nationally, about 12 percent of bridges are labeled "structurally deficient."

During the 1990s, inspections found fatigue cracks and corrosion in the steel around the bridge's joints. Those problems were repaired. Starting in 1993, the bridge was inspected annually instead of every other year.

State bridge engineer Dan Dorgan said the bearings could not have been repaired without jacking up the entire deck of the bridge. Because the bearings were not sliding, inspectors concluded the corrosion was not a major issue.

After a study raised concern about cracks, the state was given two alternatives: Add steel plates to reinforce critical parts or conduct a thorough inspection of certain areas to see if there were additional cracks. They chose the inspection route, beginning that examination in May.

"We thought we had done all we could," Dorgan told reporters near the mangled remains of the span. "Obviously something went terribly wrong."

The collapsed bridge's last full inspection was completed June 15, 2006. The report shows previous inspectors' notations of fatigue cracks in the spans approaching the river, including one four feet long that was reinforced with bolted plates.

Although concern was raised about cracks, some experts theorized it's no coincidence the collapse happened when workers and heavy equipment were on the bridge. The construction work involved resurfacing and maintenance on guardrails and lights, among other repairs.

"I would be stunned if this didn't have something to do with the construction project," said David Schulz, director of the Infrastructure Technology Institute at Northwestern University. "I think it's a major factor."

The White House said Friday the president supports "necessary funding" to rebuild the bridge. The Minnesota congressional delegation has sought $250 million.

On Thursday, the House Transportation Committee approved legislation that would waive the $100 million federal limit per state for emergency relief funds, and direct $250 million to Minnesota. The bills are supported by leaders in both chambers, and sponsors hope to get the bill passed before Congress leaves for its monthlong summer break Friday.

The Associated Press contributed to this report.