The vehicle was driving on a road in Helmand province’s volatile Sangin district — a Taleban stronghold — when it hit the bomb, said Daoud Ahmadi, a spokesman for the Helmand government.

At least five children were among the dead, he said. Another six people were wounded and all were being treated at a NATO base. No one immediately claimed responsibility for the attack — a common situation when bombs kill civilians.

The blast comes a day after twin bombings on Tuesday that left 60 dead and sparked fears that attacks in Afghanistan might be taking on a sectarian dimension for the first time.

Afghan President Hamid Karzai cut short a European trip because of Tuesday’s attacks and returned to Kabul on Wednesday to visit the scores of wounded and the bereaved families of those killed in the capital.

A suicide bomber slaughtered 59 Shiites and wounded more than 160 others Tuesday outside a shrine where hundreds had gathered. One US citizen was also among the dead, according to a statement issued by the American Embassy in Kabul.

The deceased was not a government employee, US Embassy spokeswoman Megan Ellis said, but declined to give further details. Afghans  Wednesday buried those killed in the unprecedented bombings Tuesday against Shiites as officials blamed Pakistani militants, accusing them of trying to whip up Iraq-style sectarian violence.

Karzai said after the blast that the attack on Shiites was unprecedented in scope and marked the first time that one had been carried out during a religious event.

His office said Wednesday that he had arrived back in Kabul, cutting short a trip to Britain and Germany, and planned to spend the day visiting the wounded in city hospitals.

Families gathered for funerals across the city on Wednesday. In western Kabul, a group of mourners carried four bodies in a funeral procession through the city’s largest Shiite cemetery. They carried pictures of the dead and shouted, “They are martyrs! We honor them!“

One of the mourners said no place felt safe anymore.

“Killing Muslims in front of a holy shrine, it is unbelievable,” said Mohammad Nahim, 35. “Last night I told my children not to visit any shrines after dark. It is too dangerous.” He said the graphic images of piled bodies came on the television as his family was eating dinner the night before and they all started crying.

“The man who owned the shop on my street corner, the man I bought vegetables from, he was killed in the attack,” Nahim said.

At one of the funerals, a member of the city’s Shiite council said the attack showed no one can count on the government for protection. “There have been so many attacks, even against government officials, and still they can’t stop these things,” said Mohaqeq Zada.

It remained unclear what the political reverberations of the attack could be.

The Taleban condemned the attack, which was reminiscent of the wave of sectarian bloodshed that shook Iraq during the height of the war there. Suspicion centered on militant groups based in neighboring Pakistan, where Sunni attacks on minority Shiites are common.

A man who claimed to be from Lashkar-e-Jhangvi Al-Alami, a Pakistan-based group that has carried out attacks against Shiites, called various media outlets in Pakistan to claim responsibility for the bombing in Kabul. The validity of the claim could not be determined.