New Delhi: The Congress faced a big embarrassment today over its protest letter on the controversial Agnipath recruitment scheme for the armed forces. Senior leader Manish Tewari -- who earlier handed the party moments of deep discomfort with his public criticism -- refused to sign the letter to Defence Minister Rajnath Singh, who was briefing a parliamentary committee on the scheme.

Mr Tewari had verbally supported the opposition to the Agnipath scheme. Today, he said he was in favour of modernisation but was against the implementation of Agnipath. Still, he refused to sign the letter, the sources said.

The letter, listing a set of demands, was signed by six opposition MPs including Congress's Shaktisinh Gohil, Trinamool Congress's Sudip Bandyopadhyay and Sougata Roy, Nationalist Congress Party's Supriya Sule and Rashtriya Janata Dal's AD Singh.

The committee on Defence chaired by Mr Singh has 20 members-- 13 from Lok Sabha and around 7 from Rajya Sabha -- from across the board.

The unveiling of the Agnipath scheme last month was followed by violent protests in many northern states including Bihar. The protest, which continued for a week, was backed by many opposition parties, who demanded a rollback.

Earlier this week, the Indian Air Force said it has received nearly 7.5 lakh applications under the scheme.