Mumbai: City police claimed to have curtailed Chhota Rajan's activities in the metropolis in a "big way" with the arrest of key operatives of the underworld don who challenged the cops by masterminding a number of crimes, including a senior journalist's murder and firing outside the home of Dawood Ibrahim's brother.

Since May, city police have put behind bars at least 15 members of the Chhota Rajan gang.

Rajan's close aide D K Rao, bookie Vinod Asrani, shooters Rohit Thangappan alias Satish Kalya, Umed-Ul-Rehman and other active members Anil Waghmode, and Aasid Jaan Shaikh were among those arrested in the past two months.

"With the arrest of these key associates of Rajan, we believe that we have cracked down or curtailed his activities in the city in a big way. Every day we put our all efforts to catch the wanted accused, no matter to which gang they belong to," Joint Police Commissioner (Crime) Himanshu Roy said.

"As his activities increased in the past few months, we have taken it as a challenge and determined to nab his aides involved in the various crimes," he said.

The underworld don was involved in sensational killing of the city-based senior investigative journalist Jyotirmoy Dey (56), who was shot dead by four motorcycle-borne assailants in suburban Powai on June 11.

Another instance was of firing outside underworld don Dawood Ibrahim's brother Iqbal Kaskar's residence on Pakmodia Street in south Mumbai on May 17, in which his bodyguard-cum-driver Arif Syed Abu Bukha was killed. Kaskar was not present at the spot when the incident happened.