"The interior ministry has issued instructions to all four provincial authorities to close down all Jemaat-u-Dawa's offices and keep an eye on their activities," said a senior interior ministry official on condition of anonymity because of the sensitivity of the situation.
It was not clear whether the order represented a formal ban on the group, nor whether its activists would be arrested.
Earlier Thursday, authorities in the country's largest city, Karachi, said they had closed nine premises associated with the group, apparently carrying out the order from the central government.
An Associated Press reporter outside one Jamaat office in the city said it was locked up and deserted. It was unclear what was happening at the group's large headquarters close to the eastern city of Lahore.
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 on Mumbai, India's financial center, killed 171 people and sharply raised tensions between the nuclear-armed neighbors, which have fought three wars over the last 60 years.
The U.N. Security Council panel on Wednesday declared Jamaat-ud-Dawa a front for 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.
In a statement Thursday, Prime Minister Syed Yousuf Raza Gilani said Pakistan had "taken note of the designation" and "would fulfill its international obligations." He did not elaborate.
Earlier, Jemaat's hard-line Islamist chief denied that the charity was involved in terrorism and denounced the U.N. 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.
Pakistan has promised to pursue those responsible for the Mumbai attacks.
But it complains that India has not shared evidence from its investigation, underlining the mistrust hampering U.S. efforts to avert a deeper crisis between the two countries.