Lindsay Lohan -- BUSTED in International Web of Lies (PHOTO)

Lindsay Lohan told a BIG FAT LIE when she said she was back in New York on Monday and ready to do her community service -- cause she was spotted arriving there on Tuesday!

Lindsay was seen getting dropped off at a hotel in the city -- chauffeur driven with assistant in tow, of course. Our Lohan sources confirm ... she just touched down on U.S. soil a few hours ago, which is bad for a couple of reasons.

First of all ... legal matters. LiLo is clearly NOT at the Brooklyn daycare center where she's supposed to be completing her remaining 115 hours of community service. Her deadline is May 28. Tick tock.

Secondly ... on Monday morning she said, "Happy to be home in nyc with my family and friends" Now it's clear she was still in London when she posted that on social media.

Not illegal, but y'know the old saying -- liar liar, pants on fire ... in jail because you didn't get your community service done.