4:00 PM PT -- Chicago PD confirms to TMZ Jussie told them, in a follow-up interview, about the attackers yelling, "MAGA country."

They add Jussie still had the rope around his neck when he made contact with cops at 2:42 AM. Remember, the attack happened around 2 AM.

12:43 PM PT -- Sources connected to production tell us Jussie and the rest of the main "Empire" cast members will have armed security going forward while they continue shooting in Chicago.

Lee Daniels briefly posted, but then deleted, a screen grab from a FaceTime he had with Jussie while he was in the hospital.

11:10 AM PT -- "Empire" creator Lee Daniels just expressed his outrage and horror over the attack.

11:18 AM PT -- We're told cops recently visited a Target Department Store close to where the incident happened and obtained surveillance footage. Our source says the video shows one person -- presumably Jussie -- walking down the street. Officers also visited a nearby apartment building to ask for video.

11:20 AM PT -- Law enforcement sources tell us the FBI was already investigating the letter sent to Jussie last week containing racist and homophobic slurs.

11:10 AM PT -- Fox just issued this statement ... "We are deeply saddened and outraged to learn that a member of our EMPIRE family, Jussie Smollett, was viciously attacked last night. We send our love to Jussie, who is resilient and strong, and we will work with law enforcement to bring these perpetrators to justice. The entire studio, network and production stands united in the face of any despicable act of violence and hate -- and especially against one of our own."

10:30 AM PT -- "Empire" staff held an emergency meeting Tuesday morning in Chicago to tell everyone what happened to Jussie. We're told the cast and crew were extremely upset. Several actors were already in their trailers getting ready to shoot when they got the news.

We're told there was a discussion about getting extra security on set while shooting. They have a handful of episodes left to shoot for the current season.

"Empire" star Jussie Smollett was brutally attacked by 2 men who beat him up, put his head in a noose and screamed, "This is MAGA country."

Sources directly connected to Jussie tell TMZ, the actor arrived in Chicago from New York late Monday, and at around 2 AM he was hungry and went to a Subway. We're told when shortly after he walked out on his way home, someone yelled, "Aren't you that f***ot 'Empire' n*****?"

The 2 men -- both white and wearing ski masks -- viciously attacked Jussie as he fought back, but they beat him badly and fractured a rib. They put a rope around his neck, poured bleach on him and as they left they yelled, "This is MAGA country."

Jussie took himself to Northwestern Memorial where he was treated. He was discharged later Tuesday morning.

ThatGrapeJuice.Net first posted this letter which was sent to Fox Studios in Chicago with cut out letters spelling, "You will die black f**." Our sources say the letter was sent 8 days ago.

The envelope the letter arrived in appears to say MAGA in the upper left corner.

Chicago PD tells us they are investigating the attack as a possible hate crime, and they are canvasing the area for any video.