File photo: National Security Advisor, Ajit Doval

National Security Advisor Ajit Doval today defended the execution of 1993 Mumbai blasts convict Yakub Memon, saying it was wrong to claim that Yakub was penalised as his brother Tiger Memon, the mastermind of the attack, was not caught.Mr Doval, who was delivering a lecture at Mumbai's Yashvantrao Chavan Centre, said, "It was completely wrong to say India could not catch Tiger so caught Yakub. Yakub and Tiger are standalone. Inter linkage is incorrect."The execution of Yakub Memon last week triggered a debate, with a section of civil society -- including politicians and legal personalities -- petitioning for the commutation of his death sentence.The sentence was carried out on the morning of July 30 - barely two hours after the Supreme Court opened its doors in the middle of the night to take a decision on his plea.Regarding the bigger debate over capital punishment, Mr Doval said it was a "discourse of conflict of values"."Someone tweeted me a statement by a leader in the evening, saying state-sponsored killing diminishes us all and reduces us to murderers. This argument means anyone acting in defence reduces himself to murderers," Mr Doval said.Without naming the leader - former Union minister Shashi Tharoor, who made the remark after Memon's execution - Mr Doval pointed out that the state "had to protect itself""You cannot say someone has the freedom to carry out a terrorist act, but the state does not have the right to use its coercive instruments to deny him his life," he added.Asked if he was justifying violence by the state, he replied, "Yes absolutely. Violence is justifiable for maintaining statecraft but with riders. Should it come to protecting the interest of the state, those interests are priority. The nation should stop at nothing to protect its interest."