LAHORE, Pakistan (AP) — Pakistanis lashed out Friday at the U.S., blaming its alliance with their government and its presence in Afghanistan for spurring two suicide bombers to kill 42 people at the country's most important Sufi shrine.

The reactions showed the challenge facing Washington and the Pakistani government when it comes to rallying public support against the Islamist extremism that has scarred the South Asian nation, even after an audacious attack on the moderate, Sufi-influenced Islam most Pakistanis practice.

Thousands of people had gathered late Thursday at the green-domed Data Darbar shrine in Lahore when bombs went off minutes apart. The blasts ripped concrete from the walls and left the white marble floor awash with blood. There was no claim of responsibility, but Islamist extremists consider Sufism — a mystical strand of Islam — to be heretical.

But on Friday, few Pakistanis interviewed saw militants at the root of the problem.

"America is killing Muslims in Afghanistan and in our tribal areas (with missile strikes), and militants are attacking Pakistan to express anger against the government for supporting America," said Zahid Umar, 25, who frequently visits the shrine, where 180 people were also wounded.

Pakistanis are suffering because of American policies and aggression in the region, said Mohammed Asif, 34, who runs an auto workshop in Lahore. He and others said the attacks would end if the U.S. would pull out of Afghanistan.

Several other Pakistanis interviewed blamed the Ahmadis, a minority sect that has long faced discrimination in Pakistan. On May 28 in Lahore, gunmen and a suicide squad targeted two Ahmadi mosques, massacring at least 93 people, and some Pakistanis claimed the sect must have been seeking revenge.

Others cast about for additional villains — though America's hand was seen there, too.

Washington "is encouraging Indians and Jews to carry out attacks" in Pakistan, said Arifa Moen, 32, a teacher in the central city of Multan.

Pakistani officials condemned the bombings, using language they have frequently used to try to convince the population that the fight against militancy is not one they can ignore.

"Those who still pretend that we are not a nation at war are complicit in these deaths," said Farahnaz Ispahani, a spokeswoman for Pakistani President Asif Ali Zardari.

The U.S. Embassy issued a statement Friday condemning the attack and saying it "demonstrates the terrorists' blatant disregard for the lives of the Pakistani people and the future of this country."

The targeted shrine is that of Data Ganj Bakhsh Hajveri, who lived hundreds of years ago and traveled throughout the region spreading a message of peace and love. He eventually settled in the Lahore area, and his shrine is the most revered and most popular of Sufi shrines in the nation.

Lahore, the capital of Punjab province, is a key military, political and cultural hub. The city has witnessed several audacious attacks on diverse targets over the past two years, from crowded markets to Sri Lanka's cricket team.

The Pakistani government has been accused of lacking the will to crack down on militants in Punjab, the country's most populous and most powerful region. Many of the militants are part of now-banned groups launched with government support in the 1980s and '90s to fight the Soviets in Afghanistan and pressure archenemy India.

Some recent attacks in Punjab have been blamed on the "Punjabi Taliban." The group is a relatively new network of al-Qaida-linked militants who have split off from other local insurgent groups but also has ties to the Pakistani Taliban, which has its bases in the northwest tribal regions.

The suicide bombings have fueled anger against Pakistan's weak police forces, who appear helpless to stop the killings. In the hours after Thursday's bombings, demonstrators gathered outside the shrine to protest the security lapse, only to be dispersed after police fired into the air and threw rocks at them.

Senior Lahore government official Khusro Pervez said recent intelligence alerts about possible attacks lacked details.

"The intelligence agencies alerted us that terrorists could target prominent places, shrines and mosques in Lahore. They mentioned names of major places as a possible target, but no specific information was available to us," he said.

Also Friday, militants attacked a security checkpoint on the outskirts of the northwestern city of Peshawar, killing three officers, said Safwat Ghayur, a regional commander of the Frontier Constabulary security force.

He said officers returned fire and killed some of the attackers.

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Associated Press Writer Riaz Khan in Peshawar contributed to this report.