An argument between construction workers led to a shooting at Billie Lourd's home ... TMZ has learned.
Law enforcement sources tell us ... cops responded to a shots fired call at the 'Star Wars' star's L.A. property, where there's currently a bunch of renovations underway.
We're told there was a conflict between 2 workers -- one of whom had been fired -- cops say the fired worker pulled out a rifle.
Our sources say he aimed at the worker, fired at the ground and took off. Nobody was hurt. Billie wasn't home at the time of the incident.
We're told the shooter has not been arrested, but cops are on the hunt.
Regarding all the construction ... Billie now owns the former Bev Hills homes of her late mother, Carrie Fisher, and her late grandmother, Debbie Reynolds-- which were contiguous -- and she's making one massive estate.
The mother-daughter duo lived right next to each other for 15 years before Carrie died in December 2016 and Debbie died the very next day.
Billie's rep tells us, "I can confirm that there was an incident today at the property involving a disgruntled ex-employee of the construction company working at the site, who had an issue with his former employer. The owners were not on site and had nothing to do with the dispute. Nobody was harmed and the situation has since resolved."
The 3.5-acre combined properties are reportedly worth $18 million, though with all of the construction going on ... seems likely that figure might go way up.