ISLAMABAD, Pakistan — Some of Pakistan's most influential clerics swiftly denounced U.S. strikes on Afghanistan's capital today, calling them an attack against Islam and grounds for holy war. One organization summoned Muslims to "extend full support to their Afghan brothers."

Pakistan's government, which has thrown its support to the U.S.-led coalition against terrorism, said it regretted that diplomatic efforts did not succeed and called for the U.S. action to remain "clearly targeted."

There were scattered anti-American protests in major cities, but no violence was reported.

The influential Afghan Defense Council, based in the eastern Pakistani city of Lahore, issued a call for holy war.

"It is the duty of every Muslim to support their brothers in this critical hour," council leader Riaz Durana said. "We will support the Taliban physically and morally against the aggression of America."

Munawar Hassan, deputy chief of Jamaat-e-Islami, Pakistan's most powerful religious political party, called the strikes "an attack against Islam." President Bush has emphasized that the United States has no quarrel with Islam, only with terrorists and those who harbor them.

Condemnation also came from the militant group Harakat ul-Mujahedeen, one of several organizations whose assets were frozen by the United States, Pakistan and other countries as part of a campaign against movements linked to Osama bin Laden, the suspected mastermind of the Sept. 11 terrorist attacks.

"Americans have used their might to kill innocent people in Afghanistan instead of targeting training camps," said Amar Mehdi, spokesman for the group, which advocates the independence of Indian-ruled Kashmir.

There was no immediate indication of any casualties when he spoke.

Rashid Quereshi, a Pakistan government spokesman, said Pakistan's airspace was used by U.S. and British forces to launch attacks.

In a statement, Pakistan's foreign ministry implored the United States to take "every care" to minimize harm to Afghans buffeted by years of war.

"We also hope that the operations will end soon and a concerted international effort will be undertaken to promote national reconciliation and help Afghanistan with economic reconstruction," the statement said.

Pakistan shares a 1,050-mile border with Afghanistan. Languages, ethnicities and even family ties overlap, and many Pakistanis, even those with no sympathy for the ruling Taliban militia, are reluctant to see Afghanistan attacked.

In downtown Peshawar, near the Afghan border, knots of angry men gathered, shouting "Osama! Osama!" and "America is a terrorist."

In Lahore, an organization of Muslim clerics issued a condemnation and said Americans now face a "highly critical situation" in the Muslim world.

"We appeal to all Muslims living anywhere in the world to extend full support to their Afghan brothers in this critical time," said Sazid Mir, president of Markazi Jamiat Ahl-e-Hadith.

In Lahore, hundreds of emotional Islamic clerics and students studying in pro-Taliban religious institutions staged protest demonstrations condemning America. Youths belonging to the student wing of Jamaat-e-Islami also staged demonstrations.

In the southwestern city of Quetta, near the Afghan border, Abdullah Hakim, an office assistant, blamed the United States for the crisis.

"After a few days, the world will turn in favor of the Taliban," said Hakim, 48.

And from retired soldier Mohammed Iqbal: "Any Muslim who claims that he is a Muslim will not support this attack."