ISLAMABAD, Pakistan – Pakistan closed offices of a charity linked to a militant group suspected in the Mumbai attacks Thursday, a day after the outfit was declared a terrorist group by the United Nations, an official said.

It was unclear whether the moves against nine Jemaat-u-Dawa premises in the southern city of Karachi represented the beginning of a major crackdown on the group. Its headquarters remained open Wednesday, as did other branches across the country.

Pakistan has arrested at least 20 people, including two extremists alleged by India to be key players in the Mumbai attacks, but India has made it clear it wants to see more action.

The attacks killed 171 people and sharply raised tensions between nuclear-armed neighbors Pakistan and India, which have fought three wars over the last 60 years.

New Delhi on Thursday announced a massive overhaul of its security and intelligence agencies in the wake of the attacks, which provoked a public outcry over the government’s response.

Among the new measures, the government will seek to create an FBI-style national investigative agency, beef up coastal security, better train local police, strengthen anti-terror laws and increase intelligence sharing, said Home Minister Palaniappan Chidambaram.

“Given the nature of the threat, we can’t go back to business as usual,” Chidambaram told Parliament.

Under pressure from India and the United States, Security Council panel on Wednesday declared Jamaat-ud-Dawa a terrorist group subject to U.N. sanctions including an asset freeze, travel ban and arms embargo.

U.S. officials say the group, which has offices, schools and medical clinics around the country, is a front for Lashkar-e-Taiba, a banned militant group accused by India of carrying out and planning the Mumbai assaults.

Sindh provincial home secretary Arif Ahmed Khan said nine Jemaat offices in Karachi were “sealed” Wednesday, but gave no more details.

Indian authorities have said they believe the gunmen who attacked Mumbai set off from Karachi by boat. It was unclear whether that was related to Thursday’s move.

Information Minister Sherry Rehman said in a statement that Pakistan would bring the U.N. declaration to the Cabinet for “a decision” on how to respond. She did not say when the Cabinet would meet.

Officials previously said they were weighing tough steps against Jemaat.

Jemaat’s hard-line Islamist chief denied that it was involved in terrorism and denounced the U.N’s move as an attack on religious groups. He said the group would petition the U.N. as well as national and international courts to overturn the decision.

“If India or the U.S. has any proof against Jamat-ud-Dawa, we are ready to stand in any court. We do not beg, we demand justice,” Hafiz Mohammed Saeed said at a news conference in the eastern city of Lahore.

A crackdown on Jamaat-ud-Dawa would underpin the promise by Pakistan to pursue those responsible for the Mumbai attacks.

But Islamabad complains that India has not shared evidence from its investigation of the attack, underlining the mistrust hampering U.S. efforts to avert a deeper crisis between nuclear-armed neighbors who have already fought three wars.

(This version CORRECTS ADDS Cabinet to discuss issue; ADDS material from BC-AS–INDIA-SHOOTINGS; corrects time element in lead)