The England international was targeted as he drove towards his home in Essex on Wednesday
The burly England international was targeted as he drove towards his home in Essex, east of London, on Wednesday, but sped off with his two assailants in pursuit and hastily returned to West Ham's Rush Green training ground before reporting the incident to police, who are investigating.
"He was brave because they asked for his watch with a gun and he put the pedal down and he didn't want to give him the watch," Bilic told his weekly press conference.
"He got chased for 15 or 20 minutes. It wasn't like 10 seconds so it was probably planned," Bilic said.
"I know that he was very brave to do what he did. He came back to the training ground and it stopped. But he's good, he's OK. He's not in shock and he acted as a really brave man.
"We're all asking him questions about it and he's smiling. Of course he's in a good environment now, he knows it's not going to happen now.
"When we heard it yesterday of course we were all shocked. Sometimes you hear about that happening in a foreign country, but it's happening far away, not in England.
"So we were all like, 'Here, in London, how is that possible?' Unfortunately it is a problem."
Carroll, 27, has not played since August due to a knee injury, but Bilic said he expected him to return to action after the international break.
"He will continue to do his rehab," Bilic said. "He is progressing well. He's back on the pitch -- not with us, but he's running and had no negative reaction since he started his running.
"So in two weeks we are expecting him to be back on the pitch with us."
Carroll joined West Ham from Liverpool in May 2013, having spent the previous season at the club on loan.
The former Newcastle United striker has been capped nine times by England, scoring two goals.