Jamaat-ud_Dawa chief Hafiz Mohammed Saeed, designated as a terrorist by the United Nations Security Council in the wake of the Mumbai attacks, and other militant leaders detained by Pakistani authorities cannot be tried in the absence of solid evidence against them, Defence Minister Chaudhry Ahmed Mukhtar said on Wednesday.

The government launched a crackdown against militant groups, including the JuD, to ensure that the Pakistani soil is not used by terrorists for activities directed against any other country, Mukhtar told reporters in Parliament House.

Saeed, also the founder of the outlawed Lashkar-e-Tayiba blamed for the Mumbai terror attacks [Images], had been detained under the Maintenance of Public Ordinance, under which a person could be held for up to 90 days, Mukhtar said. The period of Saeed's detention could also be extended, he added.

However, there is no "solid proof" against Saeed with the Pakistan government and India has not provided any evidence about LeT's involvement in the Mumbai attacks, Mukhtar said.

In the absence of evidence, Saeed and the others who had been detained could not be tried in a court of law, he said.

Mukhtar, who spoke to journalists after briefing the parliamentary committee on national security, did not provide details of the other militant leaders who had been detained.

Pakistan cracked down on the JuD after the UN Security Council last week declared it a terrorist group and put Saeed and three other persons on the list of terrorists subject to sanctions like a travel ban and asset freeze.

Authorities have also detained over 20 LeT militants, including its operations chief Zakiur Rehman Lakhvi, the suspected mastermind of the Mumbai attacks.

Despite India's assurance that it would not wage a war against Pakistan, the country's armed forces are on "high alert" to avert any untoward incidents that could possibly arise on the eastern border, Mukhtar said.

He also claimed the ISI agency was not involved in the Mumbai attacks.

Meanwhile, President Asif Ali Zardari [Images] said Pakistan was not apologetic to India in the wake of the Mumbai attacks.

Instead, Pakistan had acted responsibly and averted a "major military escalation" between the two countries, he said.

Zardari briefed parliamentarians from the tribal areas bordering Afghanistan on the security situation during a meeting this afternoon. He asked them cooperate with the government in tackling militancy and terrorism emanating from the tribal belt.

The President also said Pakistani soil will not be allowed to be used for any terrorist activity. Foreign terrorists will be flushed out with full strength, he said.