One of Reading's new bio-ethanol buses has been forced off the road after vandals caused more than £1,000 damage.
Eleven seat backs were ripped out of the bus as it ran between central Reading and Tilehurst on Friday night.
Another attack on a different bio-ethanol bus on Saturday along the same route saw eight seats wrecked.
Reading Buses called it "an orgy of destruction". The company said it hoped its CCTV images would help police to identify those responsible.
The company said one of the buses had been repaired with a stock of spare seats, but the other vehicle would be out of service over Christmas and New Year as new seats are sourced.
James Freeman, from Reading Buses, said: "This is the first significant attack on these high-tech buses since their introduction.
"We do our best to keep them in tip-top condition, so this is a big disappointment.
"Thanks to the CCTV cameras fitted on the buses, we have good evidence to help the police in their inquiries and we hope that they will be able to find these vandals quickly."