Jamaat-ud-Dawa's camp in Kashmir. It denies any role in Mumbai
India has urged the UN Security Council to ban a Pakistan-based Islamic charity, seen as a front for a group being blamed for the Mumbai attacks.
India's junior foreign minister E Ahamed told the UN that it should "proscribe" Jamaat-ud-Dawa, believed to be a front for Lashkar-e-Taiba.
India has blamed Lashkar-e-Taiba for the attacks.
Pakistan's PM has confirmed two senior figures in Lashkar-e-Taiba have been held and are being interrogated.
Pakistan earlier said that the pair - reported to have been held after a raid on a camp used by Lashkar-e-Taiba - would not be handed over to India.
Mr Ahamed said had requested the UN Security Council "to proscribe the Pakistani group Jamaat-ud-Dawa since it is a terrorist outfit".
"All those who were in any way responsible for the Mumbai terrorist attacks, wherever they may be, should be brought to justice," he said.
Mr Ahamed said India had acted "with restraint in the face of terrorist attacks", but it might be compelled to take action in future.
"We must do our duty to by our people and take all actions as we deem fit to defend and protect them," he said.
"The charter of the United Nations and provisions of international law, including the right of self defence, gives us the framework to fulfil these responsibilities."
Reports say Pakistan has already ordered the sealing of some offices used by Jamaat-ud-Dawa.
Pakistani Prime Minister Yousuf Raza Gilani confirmed on Wednesday the arrest of the two members of Lashkar-e-Taiba named by India as suspects in the Mumbai conspiracy.
Zaki-ur-Rehman Lakhvi and Zarrar Shah were being held for questioning, Mr Gilani told journalists in the city of Multan in the central province of Punjab.
Pakistan's UN ambassador Abdullah Hussain Haroon said he was a "a little surprised" at the force of the statement of the Indian minister.
TEN NAMED GUNMEN
Nasir, alias Abu Umar (above, Nariman House)
Abu Ali (Taj Palace)
Soheb (Taj Palace)
Fahad Ullah (Oberoi)
Azam Amir Qasab (survived)
Bada Abdul Rehaman (Taj Palace)
Abdul Rehaman Chota (Oberoi)
Ismal Khan (CST station)
Babar Imaran (Nariman House)
Nazir, alias Abu Omer (Taj Palace)
He said India and Pakistan should "stop all negative campaigns against each other".
Mr Haroon said Pakistan was ready to cooperate with India in the investigation of the attacks.
"Not only are the terrorists not linked to Pakistan in any way, we too are their targets and we too continue to be their victims," he told the council.
On Tuesday, Indian authorities released the names or aliases of the nine suspected militants killed during last month's attacks in Mumbai.
Photographs of eight of the men were released - the body of the ninth was said to have been too badly burned.
Police said all were from Pakistan. They did not say how this was known but one gunman, named as Azam Amir Qasab, survived and has been interrogated
The attacks began on 26 November and left at least 170 people dead.
Pakistan's raid on the Lashkar-e-Taiba camp on Sunday was praised by the US as a "positive step".
In addition to the detention of Mr Lakhvi, Pakistan said it had also arrested Masood Azhar, founder of the Jaish-e-Mohammad militant group.
He is one of the most wanted men in India. Jaish-e-Mohammad is accused along with Lashkar-e-Taiba of taking part in the attack on India's parliament in 2001 which led the two countries to the brink of war.
Mr Azhar is reportedly on a list of people Delhi has demanded Pakistan hand over.