Gunfire broke out during a street brawl in Mill Hill in the early hours of this morning.
Police were called after a fight broke out near the Railway Tavern in Hale Lane shortly before 1am.
But when officers arrived the fighting had already ended.
The road has been closed for more than eight hours while police investigated and searched the area for weapons.
But a Met Police spokesman said no one at the scene had been injured, no victims have been found and no weapons recovered.
Anyone with information is asked to call police on 101.
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