"No one was injured in the incident and the youth, Raju Tomar, a resident of Ambedkar Nagar slum in Dadar, has been arrested," the official said.
"During routine checking at around 1.30 am, a youth attempted to evade the police at the CST. When they tried to nab him, he fired one round at them," said Assistant Commissioner of Police, Government Railway Police, Bapu Thombre.
The youth was pursued and caught by the police personnel present at the terminus. A country-made revolver and one `live' round were recovered from him, Thombre added.
"He has given conflicting versions on why he was carrying the revolver. First he claimed he was going to avenge his father's death and the second time he claimed it was to resolve a love affair," Thombre said, adding that further investigations were on.
Security has been stepped up at the historic terminus after the November 26 Mumbai terror strikes, in which over 50 persons were killed when two terrorists fired indiscriminately at the railway station.