Gwent Police say they are working to establish what happened after a schoolbus left the road in the village of Llanfach this morning.
The schoolbus was carrying 20 children between 8 and 12 years old and three adults.
No injuries are reported. There have been no arrests and enquiries are ongoing. The road was closed while the bus was recovered.
Bus company Stagecoach says it will do all it can to assist police in their investigation.
More top news
TV star will be your DJ for the night at a charity 'dance-a-thon' in Cardiff.
The Royal Mint has announced that it is to launch the UK’s first £50 coin to celebrate the Queen becoming the longest-reigning monarch.
A campaign has been launched to target drivers who risk theirs and other people's lives by driving whilst under the influence of alcohol.