A tree is currently blocking the road in Alfriston Road, Seaford.
Writing on Twitter, PC Elliot said: “Road closure in place, with East Sussex Highways requested to attend.
Brighton and Hove Buses announced that the 12A service to Eastbourne will divert from Cemetery Gates to Sutton Corner.
It will then take the A259 to resume normal route from Chyngton Lane.
From Eastbourne it will continue along the A259 to Sutton Corner and left at Cemetery Gates to resume the normal route.