KING OF PRUSSIA, Pa. (CBS) — Police say there was a smash and grab robbery at the Tourneau watch store in King Of Prussia Mall Friday night.

A little after 8 p.m., police say five masked men entered the store, restrained the security guard at gunpoint while they smashed the glass display case with sledge hammers, stealing numerous watches.

Police say the robbery lasted less than a minute before the suspects fled the store.

The five robbers were described by witnesses as black males wearing masks and clothing to prevent their identity from being revealed. The security guard suffered a minor injury from being struck by one of the suspects, according to police.

The amount of merchandise stolen has not yet been determined.

Upper Merion police ask that anyone with information on the robbery to call 610-265-3232.

Tourneau Inc. was robbed last July.

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