A dove sits on the flagpole as an Indian Border Security Force soldier lowers the Indian national flag during the "Beating the Retreat" ceremony Wednesday at the joint border check post of Wagah, India.
India, which has asked for concrete evidence that Pakistan is quelling militant groups, is urging the United Nations to declare the charity, Jamaat-ud-Dawa, a terrorist organization.
A crackdown on Jamaat-ud-Dawa would underpin the promise by Pakistan's civilian government to pursue extremists blamed for last month's terrorist attack, which killed 171 people in India's commercial capital.
But Pakistani officials say India has not shared evidence from its investigation of the attack, underlining the mistrust between the nuclear-armed neighbors that is hampering U.S. efforts to avert a deeper crisis.
Prime Minister Yousuf Raza Gilani said Pakistani authorities have detained Zarrar Shah, an alleged leader of Lashkar-e-Taiba, the banned Islamic militant group India says was responsible for the Mumbai attack.
Indian news reports citing intelligence officials identified Shah as Lashkar's communications chief and said he worked out ways for the group's leaders in Pakistan to stay in touch with the 10 gunmen during the three-day siege in Mumbai.
The New York Times has reported that the attackers and their handlers used Internet phone services to make it harder for investigators to trace their calls.
Gilani also confirmed that Zaki-ur-Rehman Lakhvi, another alleged plotter identified by India, was detained during a raid Sunday in Pakistan's portion of Kashmir. That predominantly Muslim region in the Himalayas is claimed by both nations and has been the focus of two of their three wars since 1947.
The prime minister said Pakistani authorities had staged raids on militants based on information released by Indian authorities through the media.
"That is a good message to our neighbors and the rest of the world that Pakistan is a responsible nation. We want to defuse this situation," Gilani said in Multan, a central Pakistani city India says was the hometown of two of the Mumbai attackers.
U.S. officials have told Pakistan that it must go beyond mere arrests and prevent any repeat of the Mumbai attack, whose victims included six Americans. India released information Tuesday purporting to show that all 10 gunmen in Mumbai were from Pakistan.
The chairman of the U.S. Joint Chiefs of Staff underlined the Bush administration's position Wednesday, praising Pakistan's steps so far but adding that it will take time to see how serious the crackdown is.
"We measure by deeds," said Adm. Mike Mullen, who visited Pakistan and India last week.
Washington wants the South Asian rivals to resume a painstaking peace process so Pakistan can focus on fighting Taliban and al-Qaida militants along the Afghan frontier.
But dismantling Lashkar will be politically dangerous for Pakistan's leaders because of the group's leading role in the dispute with India over Kashmir.
Pakistan's military and intelligence services are widely believed to have helped create Lashkar as a proxy fighting force in India's part of Kashmir, where Muslim separatists have engaged in a long insurgency.
While Pakistan's young civilian government has voiced a strong stance against Islamic extremism and reached out to India, there are doubts that the military, which has ruled for about half the country's 61-year history, will turn decisively against its unofficial allies.
The arrests of Lakhvi and Shah are "a minor first step which the government has taken as a gesture," said Ayesha Siddiqa, a Pakistani defense analyst.
After a 2001 attack on India's Parliament by alleged Pakistani militants, Pakistan banned the main groups fighting in Kashmir and arrested two of their leaders. But the leaders were freed without charge months later.
In a sign that Pakistan's current government wants to go further, Pakistan's ambassador to the United Nations told the Security Council on Tuesday that police are investigating Jamaat-ud-Dawa and other groups and might impose punitive measures, including a freeze on their finances.
"A plan is being prepared to ensure effective government supervision, as required by this body and others, of the various welfare organizations," Abdullah Hussain Haroon told the council.
An official in Pakistan's ruling party told The Associated Press on Wednesday that the government would ban the group "once we have proof" of its involvement in illegal activities.
Neither that official or a second who also confirmed the investigation would say when a decision on any sanctions might be made. Both officials insisted on anonymity because of the issue's sensitivity.
Jamaat-ud-Dawa, which appeared after Lashkar's banning and runs schools and medical clinics in Pakistan, denies any link to Lashkar. But Washington says it is a front for Lashkar and also has ties to al-Qaida. Some analysts suspect the charity may supply recruits for militant operations.
The charity's leader, Hafiz Mohammed Saeed, repeated his group's denial of links to Lashkar. "No Lashkar-e-Taiba man is in Jamaat-ud-Dawa and I have never been a chief of Lashkar-e-Taiba," he told Pakistan's Geo television Wednesday.
U.S. officials contend that Saeed, one of the suspected Lashkar leaders detained and released in 2002, is still the overall leader of the extremist group.
Associated Press writers Stephen Graham and Nahal Toosi in Islamabad, Khalid Tanveer in Multan, Sam Dolnick in New Delhi, Ramola Talwar Badam in Mumbai and John Heilprin at the United Nations contributed to this report.