New Delhi, Oct 22 (IANS): DMK chief M. Karunanidhi met Congress president Sonia Gandhi here Saturday in what was described as a "courtesy call", even as a special CBI court framed charges in the 2G spectrum case in which his daughter and MP Kanimozhi is one of the accused.

Karunanidhi met Sonia Gandhi at her 10 Janpath residence for 15 minutes, Congress sources said. "It was just a courtesy call," Karunandihi told reporters after the meeting.

This was the first meeting of former Tamil Nadu chief minister Karunanidhi with Sonia Gandhi after Kanimozhi and former minister A. Raja of the DMK were jailed in the 2G spectrum case.

DMK is a key ally in the Congress-led United Progressive Alliance (UPA) government.

Party spokesperson T.K.S. Elangovan said here that Karunanidhi had met Sonia Gandhi to enquire about her health.

"We are all part of the UPA. It is natural for one leader to meet the chairperson (Gandhi). Especially after the return of Sonia Gandhi after treatment," after a five-week hospitalisation abroad following surgery, he said.

However, the meeting assumed significance in view of the 2G case.

Karunanidhi is likely to meet Kanimozhi in Tihar Jail Saturday afternoon, party sources said.

He had met Law Minister Salman Khurshid Friday night and Home Minister P. Chidambaram Saturday morning.