A PSNI statement said: “Motorists are advised that the road is currently closed at the end of the Monadore Road, Claudy, due to a serious one vehicle road traffic collision. The Altinure Road is also closed.
“Please seek an alternative route for your journey.”
Earlier, motorists were asked to exercise extreme caution due to a significant oil spill on a Northern Ireland road this evening.
The spill has occurred on the Mulvin Road, Victoria Bridge, Country Tyrone.
PSNI also asked drivers to seek an alternative route for their journey.