Baghdad, Iraq ? A suicide bomber blew himself up Thursday among pilgrims outside Iraq’s holiest Shiite shrine, killing 35 people and wounding 122. A radical Sunni group claimed it carried out the attack in the southern city of Najaf, warning Shiites they are not safe even “deep in your regions.”

At least 37 other people were killed or found dead Thursday elsewhere in Iraq, police said. They included five civilians who died when a mortar shell struck a cafe in a Shiite Muslim area of north Baghdad.

The suicide bomber struck as he was being patted down by a security guard in front of the Imam Ali mosque in Najaf, which contains the tomb of Prophet Muhammad’s son-in-law, Ali, and is one of the world’s most sacred shrines for Shiites.

An Iraqi army statement put the casualty toll at 35 dead and 122 injured.

Prime Minister Nouri al-Mailiki, a Shiite, denounced the bombing as a “barbaric massacre” conducted by Sunni extremists and Saddam Hussein loyalists “seeking to inflame sectarian” passions.

A Sunni extremist group – Jamaat Jund al-Sahaba or Soldiers of the Prophet’s Companions – claimed responsibility for the blast, warning Shiites in an Internet posting that “our swords are capable of reaching deep in your regions.”

“So stop killing unarmed Sunnis and stop supporting the crusaders,” or the Americans, the statement said. “Otherwise, wait for such operations that will shake your regions like an earthquake.”

The blast shattered souvenir stalls across from the shrine, littering the narrow streets with broken perfume bottles, sandals, prayer beads and pools of blood. Volunteers picked up the human remains.

An Iranian woman was among the dead and at least nine Iranians, including two women, were wounded, Iranian state television reported.

It was the deadliest attack since July 18, when 53 people were killed by a suicide bombing in Najaf’s twin city of Kufa, about 100 miles south of Baghdad.

Thursday’s bombing represented a brazen assault on the Shiite community, which reveres Najaf as the world center of Shiite theology. The late Iranian leader Ayatollah Ruhollah Khomeini lived for years in exile in Najaf; Sheik Hassan Nasrallah, the head of Lebanon’s Hezbollah guerrillas, studied there.