MANILA, Philippines >> A passenger bus plunged from an elevated highway in suburban Manila and fell onto a van passing below Monday morning, killing at least 21 people and injuring 20 others, police said.

TV footage showed a number of bodies strewn around the bus wreckage with police officers nearby. The van was an unrecognizable pile of smashed white metal.

The bus veered off the Skyway, as the elevated road is called, and crashed onto the van in suburban Paranaque city at dawn, said police Superintendent Elizabeth Velasquez. The van’s driver was killed and the bus driver was in serious condition in a hospital, she said.

It wasn’t immediately clear what caused the accident but the highway was wet from rain, said Ivy Vidal, a spokeswoman from Skyway Operations and Maintenance Corp.

Irene Sisperes, a motorist who witnessed the accident, said she was driving with her daughter at 80 kilometers per hour (50 mph) when the bus overtook her car. She estimated that the bus was traveling at between 100 kilometers per hour (62 mph) and 110 kph (68 mph).

She said it was still dark and it was raining when the accident happened.

“After a few meters, I saw the bus fell and I shouted, ‘The bus fell, the bus fell’,” she told DZMM radio, adding there were no other cars nearby.

Sisperes said she saw the damaged railing of the highway and some debris and reported the incident at the toll gate.