The Hyderabad Police conducted searches at the residences of several foreigners in the city on Thursday, many of them being Africans.
About 50 teams comprising of officials from the police, intelligence and immigration department conducted the searches in the areas of Hyderabad, Cyberabad and Rachakonda since early in the day.
The searches took place in Banjara Hills, Jubliee Hills, Mehdipatnam, Asif Nagar, Toli Chowki, Bundlaguda, Alwal, LB Nagar, Neredmet and other areas.
They checked visas and other documents of the foreigners, including students, to verify if they were staying legally.
The searches followed the arrests of some foreigners during the investigation in a drug racket.
Officials said they identified some foreigners staying on in the city even after the expiry of their visas. They said the process would be started to deport them.
In the first week of August, a Special Task Force of the Telangana Excise and Prohibition Department took a South African national into custody from the Rajiv Gandhi international Airport in Hyderabad, for allegedly carrying cocaine.
"The South African, identified as Alex Victor, aged about 40, was taken into custody with cocaine (commercial quantity), after he came out of the airport after landing from Mumbai," PTI quoted a senior Excise official as saying.
This also comes two weeks after the arrest of Dutch national Mike Kamminga on July 26 from his house in Hyderabad.
Officials, who detained him from Nanakramguda, stated that he was found in possession of DMT (Dimethyltryptamine).
In June, a sensational racket busted by authorities found that about 1,000 students of leading private schools and colleges in the city were using high-end drugs such as LSD and MDMA. Some of them were as young as 13.
The racket also exposed the dark underbelly of Tollywood, as the dealers were also supplying drugs to several personalities from the Telugu industry.
Investigators had earlier said that Mike Kamminga's arrest was being considered a major breakthrough as he was reportedly supplying the drugs to peddlers from Europe.
Officials also said that he might be the link between the drug bust and its connection to techies in Hyderabad from several MNCs, who were consuming drugs.