The Defense of Pakistan Council rallies, which are characterized by virulent anti-American speeches and gun-toting stewards, have alarmed Western diplomats and many Pakistanis; and the ease with which they have been organized has stoked news media suspicions that the group enjoys tacit support from the military and its powerful intelligence service, the Inter-Services Intelligence Directorate, or ISI, possibly as a means of pressing Washington.

Stephen Tankel, an assistant professor at American University in Washington and author of a book on Lashkar-e-Taiba, said the reward’s immediate goal could be to diminish Mr. Saeed’s profile. “I see this naming and shaming as a way of putting pressure on Pakistan,” he said. “It seems that the U.S. is concerned with Saeed’s appearances at rallies and wants the ISI to put him back in a box.”

In many ways, Mr. Saeed embodies one of Pakistan’s greatest problems of the past decades: the struggle to rein in homegrown militant groups that flourished under the military’s protection — or at least its blind eye.

The former military ruler, Pervez Musharraf, banned Lashkar-e-Taiba in 2002, but it quickly re-emerged under the guise of its charity wing, Jamaat-ud-Dawa. Attempts to prosecute Mr. Saeed for what is said to be his role in various attacks have failed, as have efforts to restrict his movements through house arrest. He has been on a list of people and groups linked to terrorism and subject to United Nations sanctions since 2008.

The greatest problem lies in his ambiguous relationship with the ISI, which nurtured Lashkar-e-Taiba in the 1990s to fight Indian soldiers in Indian-occupied Kashmir. Over the past decade, the militant group has expanded its activities to include attacks on Indian civilians, Western tourists and Jewish clerics. In Afghanistan, its militants have emerged as a factor in the war in the east.

ISI officials insist they effectively lost control of the group after cutting their ties to it in 2002. But they have also failed to stop its fund-raising and recruitment through Jamaat-ud-Dawa, which has run substantial charity operations across Pakistan, particularly after an earthquake in 2005 and widespread floods in 2010.