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'Balthazar' Owner Keith McNally Rats on You!!!! ... After Nasty Bezos-Sanchez Remarks

The beef between NYC restaurateur Keith McNally and Jeff Bezos and his fiancée, Lauren Sanchez, just took an odd turn ... and it involves a dirty rat!

McNally – the owner of Manhattan's famed Balthazar bistro – jumped on Instagram Friday to report a suspicious middle-aged man had one drink at the establishment before quickly paying and emptying a bag of 5 white rodents inside the joint.

Instagram/ @mmanningbarish

Customers enjoying their meals freaked out at the sight of the critters scurrying around their feet. One diner shot a cell phone video of a small rat racing across the floor, but it was dark in color, poking a hole in McNally's description.

The wait staff jumped in to capture the critters, picking them up with napkins as the alleged perp fled.

In his IG post, McNally called the whole ordeal a "SET-UP," adding he felt "sorry that the 5 domesticated white mice were exploited this way." It appears he's since taken the claim off his page.

As you may know ... McNally recently criticized Sanchez out of the blue, calling her "SMUG" and "absolutely revolting." He also referred to Bezos in the same way.

Based on his "SET-UP" comment, McNally seems to be suggesting Sanchez/Bezos might be behind the rat infestation at his eatery.

Interesting tidbit ... the woman who shot the mouse video later uploaded it to her IG page, using McNally's exact words about Sanchez – "absolutely REVOLTING" -- to describe the situation in the restaurant.

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