The A5 in Northamptonshire is closed in both directions after a "police-led incident", the Highways Agency has reported.
In a statement issued this evening, the agency said the road was closed between the A43 at Towcester and the A45 at Weedon Bec.
The agency said Northamptonshire Police was leading the incident response and has issued details of the diversion around the closure .
There are no confirmed details as to the nature of the incident.
The diversion is as follows:
◾ At Towcester exit the A5 on to the A43 eastbound
◾ Follow the A43 to J15a of the M1
◾ Take the M1 northbound to J16 and exit
◾ Follow the A45 westbound to Weedon Bec
◾ Re-join the A5 at the Weedon Bec roundabout
The above route is marked out on road signs with a solid circle symbol.
◾ At the Weedon Bec roundabout take the A45 eastbound
◾ Follow the A45 to the M1 J16
◾ Take the M1 southbound to J15a and exit
◾ Follow the A43 westbound to Towcester
◾Re-join the A5 at the Towcester roundabout.
The above route is marked out on road signs with the solid square symbol.
Delays are likely on approach to the closures, with additional journey times also expected on diversion routes.
For more traffic information visit the Traffic England website, our travel apps' or call the Customer Contact Centre on 0300 123 5000.