A bomb exploded on a bus in Bat Yam on Sunday afternoon, but nobody was injured because an alert passenger had spotted the device and the bus driver had ordered the vehicle evacuated.

A police sapper was trying to defuse the bomb when it exploded. He was taken to the hospital for an examination, but was found not to be injured and was quickly released, a police spokesman told The Times of Israel.

Police said that early indications pointed to an apparent terror attack. They urged the public to be on the alert for additional bombing attempts.

Police were searching for the individual who planted the bomb and possible accomplices.

The explosion badly damaged the Dan No. 240 bus, which was stopped at the time on the corners of Mivtza Sinai and Katznelson streets in the coastal city, which borders Tel Aviv on the south. All the windows were either blown out or shattered, and seats were mangled.

The last passengers were evacuated three minutes before the device exploded, Channel 2 news reported.

“A passenger alerted the driver about a suspicious bag located behind the back door of the bus,” a spokesperson for the Dan bus company said. “The driver stopped the bus and examined the bag. He saw electrical wires attached to the bag and ordered all passengers off the bus, leaving after them. He then called police sappers.”

Bus driver Michael Yoger deflected praise that he had saved the dozen or so passengers on the bus.

Michael Yoger (screen shot: Channel 2)

Michael Yoger (screen shot: Channel 2)

“I’m a hero? What hero? One of the passengers told me there’s a suspicious bag on the bus. I asked whose bag it is. When they told me it didn’t belong to anyone, I took the passengers off the bus. I stopped at the bus stop and the people got off, the police arrived at the scene and ten minutes later the bus exploded,” he said.

The passenger, later named as David Papo, noticed the suspicious bag, opened it, and saw a pressure cooker with wires extending from it. He then alerted driver Yoger.

President Shimon Peres later phoned and thanked the bus driver and the passenger who discovered the explosive, saying their actions saved lives.

“The nation owes you a debt of gratitude and I would like to personally congratulate you for this act of bravery,” Peres told bus driver Yoger.

Initial reports said the bomb contained some 5 kilograms of explosives — enough to cause immense devastation. The bomb that blew up a bus at Burgas airport in Bulgaria in 2012, killing five Israelis and a local driver, by way of comparison, contained 3 kilograms of explosives.

“At this point in time we are under the impression that the incident was nationalistically motivated. I urge the public to be aware and report any suspicious activity to the police,” Public Security Minister Yitzhak Aharonovitch said.

The Dan spokesperson praised the passenger and driver for their quick thinking.

The Associated Press contributed to this report.