MIAMI • An engineer had reported cracks on a newly installed pedestrian bridge two days before it collapsed on a busy road, killing at least six people, state officials said.

The report, by the lead engineer with the company in charge of the bridge's design, was made in a voicemail message left for a Florida Department of Transportation employee.

That employee was out of the office, however, and did not receive it until last Friday, a day after the collapse.

The cracking was on the north end of the span but the company did not consider it a safety concern, according to a recording of the message released by the transportation department.

"We've taken a look at it and obviously some repairs or whatever will have to be done, but from a safety perspective, we don't see that there's any issue there, so we're not concerned about it from that perspective," said engineer W. Denney Pate. "Although, obviously, the cracking is not good and something's going to have to be, you know, done to repair that."

The transportation department said last Friday that "the responsibility to identify and address life-safety issues and properly communicate them is the sole responsibility of the FIU design-build team", referring to Florida International University, which commissioned the bridge.

The bridge was suspended from cables which came loose, and while they were being tightened the whole thing collapsed, Florida Senator Marco Rubio wrote on Twitter.

Miami-Dade Fire Rescue Division chief Paul Estopinan said that at least eight cars were trapped when the 950-tonne bridge suddenly gave way last Thursday.

Miami-Dade county police spokesman Alvaro Zabaleta told reporters that on Friday, rescue operations had shifted to one of body recovery, with engineers fearing the support structures at either end of the bridge could also come down. "The entire bridge is in jeopardy," he said.

NYTIMES, AGENCE FRANCE-PRESSE