5:00 PM PT -- Law enforcement tells TMZ it's apparent items were taken from Disick's home, but they're not sure what was stolen because they have not yet spoken with Disick. Our sources say it appears the house was at least partially ransacked. And now we know why cops raced to the scene ... there was a silent burglar alarm that was activated. As of now there are no leads.

3:08 PM PT -- Neighbors around Scott's home tell TMZ they did not hear an alarm go off during the burglary. We're told there was police activity there up until at least 3 AM. One neighbor tells us there was more car activity than usual at the house Saturday morning, but it was quiet from at least 11 PM until cops showed up.

Scott Disick is the latest celeb to get hit by burglars ... this time someone broke into his home in the wee hours of Sunday morning.

Law enforcement sources tell TMZ burglars broke through a rear door of Scott's Hidden Hills home, and deputies responded around 1 AM.

Nobody was home at the time of the burglary. As we reported ... Scott was celebrating his 34th birthday in Vegas.

It doesn't seem coincidental that Scott was at a well-publicized gig in Vegas, hundreds of miles from his Hidden Hills home. Various people were posting pics and videos of Scott inside 1 Oak where he was celebrating his birthday. An hour later, his house was hit.

You'll recall, Scott's house was broken into last year - almost to the day - while he was in Cannes.

It's unclear what was taken this time, or whether his burglar alarm was on.