A four-member NADA team, headed by doctor Ankush Gupta, raided the premises of NIS and searched rooms of the campers, besides taking urine samples. The raid started around 1 pm.

The raid and taking of samples was not directed to track and field athletes only but to all the campers at the NIS.

"A four-member team raided NIS, searched the rooms of the campers there and took urine samples also for dope testing. Dr Ankush Gupta was the team leader and there was one lady officer of NADA also," NADA Director General Rahul Bhatnagar said.

Bhatnagar, however, said that the raid was a part of the routine drive of NADA to increase monitoring of athletes from using performance-enhancing drugs.

"It was not directed to track and field athletes. The team raided the rooms of other non track and field campers also and took samples from them. It was part of our routine drive under our increased vigilance to tackle doping," he said.

Eight track and field athletes tested positive for anbolic steroids in one of the worst doping scandals in the country and six of them trained at the NIS Patiala.

Mandeep Kaur, Sini Jose and Ashwini Akkunji, who were part of the 4x400m relay quartet that won gold in the Commonwealth and Asian Games last year, and three other quartermilers Jauna Murmu, Tiana Mary Thomas and Priyanka Panwar were training at NIS when they were caught for doping. Of the other two dope-tainted athletes, long jumper Hari Krishnan Muralidharan trained at Pune while Sonia was not in any national camp.

The 'B' samples of Mandeep, Sini, Jauna and Mary Thomas have also tested positive while the results of 'B' samples of Ashwini and Priyanka are awaited.

Hari Krishnan and Sonia are yet to test their 'B' samples.

Sports Minister Ajay Maken has ordered an inquiry by former Punjab and Haryana High Court Chief Justice Mukul Mudgal to probe into the doping scandal.