The A75 is currently closed between Annan and Dumfries and is expected to remain closed for up to five hours, after a road accident early this morning.
The westbound diversion route is via A75 at Ladyfield, onto the B7020 to Dalton and Lochmaben, onto the A709 and then to the A75 at Dumfries.
The eastbound diversion is the reverse route.
Police are asking motorists to avoid the area if possible.
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The family of Christian Pay, who died on Friday after suspected substance abuse at a festival, have paid tribute to the Millom teenager.
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Christian Pay's family say he was "loved by all" and had "the heart of a lion". The 18-year-old died after falling ill at the festival.