NEW DELHI – Indian opposition lawmakers staged a noisy protest and walked out of parliament on Thursday, branding government efforts to improve ties with Pakistan a sell out of national interest.

Prime Minister Manmohan Singh has been under attack for a joint statement he signed with Pakistani counterpart Yusuf Raza Gilani agreeing to delink the issue of terrorism from a broader peace process India halted after November's Mumbai attacks.

He also drew flak for agreeing to include in the joint statement a reference to the Pakistani province of Baluchistan, where Pakistan accuses India of fomenting an insurgency. New Delhi denies the charge.

Foreign Minister S.M. Krishna told parliament on Thursday that India had nothing to hide on Baluchistan which is why the two prime ministers agreed to include it in the statement.

This is a strange concept that we have nothing to hide, Bharatiya Janata Party (BJP) leader Lal Krishna Advani said, adding Singh should have objected to the inclusion of a reference to Baluchistan.

And furthermore, if it was to be included, then he should have said there that India has nothing to do with what is happening in Baluchistan, Advani said before leading the opposition walkout.

Pakistan says India arms its Baluch rebels and directs anti-Pakistan activities from Indian consulates in Kandahar and Jalalabad in Afghanistan.

India broke off a five-year-long formal peace process after the attacks on Mumbai by Pakistan-based militants who India says must have been helped by Pakistani security agents.

Islamabad denies state agencies had any role in the attacks that killed 175 people.

(Reporting by Krittivas Mukherjee; Editing by Bappa Majumdar and Nick Macfie)