New Delhi, Dec. 10 -- The Competition Commission of India (CCI) has engaged attorney general R Venkataramani, the country's highest-ranking law officer, to fight its case against various current and former online sellers of Amazon and Flipkart, including Cloudtail India Pvt Ltd, Appario Retail Pvt Ltd and Samsung India Electronics Pvt Ltd, two people informed about the development said.

These companies have filed writ petitions in various high courts, challenging the CCI's antitrust probe against the two e-commerce giants, which was later expanded to include the sellers as well.

CCI moved the Supreme Court last week, seeking to combine two dozen writ petitions filed in the high courts of Karnataka, Punjab and Haryana and Madras by curre...