Six people are missing after the nearly two-mile-long Francis Scott Key Bridge in Baltimore collapsed Tuesday after being hit by a ship. The number of victims could have been much higher, but the SOS issued by the ship’s crew allowed traffic on the bridge to be quickly closed.

Radio recordings of calls from emergency services, published by CNN, reconstruct the moments before the collapse of a huge structure.

Immediately after the ship sent an SOS message, the authorities mobilized to stop traffic on the bridge, which, considering it was night, was not very heavy.

“I need one of you on the south side, one of you on the north side, stop all traffic on the Key Bridge. There’s a ship approaching that has just lost direction, so until we can get it under control, we have to stop all traffic,” the official said, according to recordings cited by CNN.

After that, reports from the teams came in, and the bridge collapsed about 90 seconds later, according to the source cited.

“The entire bridge just collapsed. (…). The whole bridge just collapsed,” one person can be heard on the recordings.

“Do we know if there was a traffic stop?” another says later.

“I can’t go over to the other side, sir. The bridge is broken,” answered another.

Currently, it is not known why 8 workers were left on the bridge, who were repairing it. Two of them were rescued after the accident, and the other six are still being sought.

“These people are heroes. Last night they saved lives”

Maryland’s governor said an SOS signal sent by a drifting ship allowed authorities to stop traffic on the bridge.

“We are thankful that between the Mayday and the destruction of the bridge, we had officials who were able to stop traffic to prevent more vehicles from coming onto the bridge,” said Gov. Wes Moore. “These people are heroes. They saved lives last night,” he said.

According to the governor, the ship was heading towards the bridge “at a very high speed” when it hit the pylon.

An unclassified Cybersecurity and Infrastructure Security Agency report cited by ABC News shows that the container ship “lost motion” while leaving the Port of Baltimore.

“The vessel advised the MD Department of Transportation (MDOT) that it had lost control of the vessel and that a collision with the bridge was possible,” the report said. “The ship crashed into the bridge, causing a complete collapse,” the message reads.

• VIDEO Moment of bridge collapse in Baltimore. Built in 1977, more than 12.4 million vehicles drove over the bridge last year