A bridge collapse on the campus of Florida International University in Miami has left at least four people dead.

Cables that suspended the bridge had loosened and were being tightened when it collapsed.

The 911 call came in just before 2 p.m. Thursday.

Police encountered several vehicles crushed under the 950-ton concrete span, and quickly shifted into a search and rescue mode.

The bridge was designed to give students and faculty a safe way to cross the busy intersection.

The $14.2 million project took years of planning.

Just last week, local officials touted the bridge as state of the art, highlighting the project's speedy construction technique.  The main section of the walkway was swung into place just a few days ago.

The cause of the collapse remains unclear.  Investigators with the National Transportation Safety Board arrived on the scene Thursday night.

Florida's governor says if there was any wrong doing or corners cut that led to the collapse, those people would be held accountable.