The U.S. ambassador to Afghanistan says this week's deadly attacks on Shi'ites in Afghanistan will not spark a cycle of sectarian violence in the war-torn country.

Ryan Crocker said Saturday in Kabul he did not foresee the attacks transforming into a sectarian conflict, based on the reaction of the Shi'ite leadership who have called for “calm.”

Two blasts, including a suicide bombing near a Shi'ite shrine in Kabul, killed at least 59 people Tuesday on Ashura, the holiest day of the Shi'ite Muslim calendar.

Crocker said the attacks had been orchestrated by militants outside of Afghanistan. He said he could not authoritatively say the bombing was carried out by the Pakistan-based Lashkar-e-Jhangvi al-Alami, even though the militant group has claimed responsibility.

The U.S. ambassador also said he had seen no evidence that the Haqqani network, which Washington has blamed for a number of attacks in Afghanistan, was involved in the blasts.

In northern Afghanistan Saturday, a bomb planted on a bicycle exploded, killing two people, including a member of Afghanistan's peace council. Sixteen people were wounded in the attack in Kunduz city.

In the south, authorities say a roadside bomb killed three civilians in the Khakrez district of Kandahar province on Saturday.