The CBI has taken up investigation into allegations of politicians phones being tapped under the previous Congress-Janata Dal government in Karnataka, officials said on Saturday.

The agency has filed an FIR on a request from the Karnataka government headed by Chief Minister B S Yediyurappa.Yediyurappa had announced a CBI probe amid signs that the scandal was gaining political steam ever since disqualified JD MLA AH Vishwanath, who served as JD state president and turned rebel, accused the HD Kumaraswamy government of tapping phones and spying on more than 300 people, including him.

Congress leaders, including Siddaramaiah, M Mallikarjuna Kharge and home minister in the alliance government MB Patil, had sought a probe while another key party leader and former minister DK Shivakumar has rejected the snooping charges and appeared to side with Kumaraswamy.

According to reports, phones of those close to Siddaramaiah, who was the then coalition coordination committee chief, too had come under the watch.