The Tandragee Road in Newry has been closed in both directions at the junction of the Fiveways Roundabout.
It is believed this road may be closed for some time and motorists are being advised to avoid.
Police are advising travel along Armagh Road or via the Carnbane Industrial Estate as an alternative route.
It is understood that police have closed the road due to a serious assault overnight.
There are no further details.
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