Kabul: The US ambassador to Afghanistan said on Saturday that he does not think this week's deadly suicide bombing at a Shiite shrine in Kabul will spark a sectarian war between religious groups in the country.

In a briefing with reporters at the US Embassy in Kabul, Ryan Crocker also said he believed that the attack was likely to have been planned in Pakistan.

"I do not see this turning into a sectarian conflict just looking at the reactions on the part of the Shia leadership, calling for calm," Crocker said.

He said that Tuesday's attack, which killed 56 people and wounded more than 160 others, might have been orchestrated by a consortium of militant groups outside the country.

"Virtually every significant attack I'm aware of where I have gotten some information either came out of tribal areas in Pakistan or (the southern Pakistani region of) Balochistan. There does indeed seem to be a pattern," he said.

Many in Afghanistan blame the Pakistani militant group Lashkar-e-Jhangvi for the attack, which occurred on the last day of Ashoura, a Shiite festival marking the seventh-century death of Imam Hussein, the Prophet Muhammad's grandson.

Crocker, who spent three years as US ambassador to Pakistan, said he could not say authoritatively that the bombing was carried by Lashkar-e-Jhangvi.

He said that the group was weak, and he doubted that the group had any Afghan affiliate.

"They were a pretty seriously weakened organization when I was there (in Pakistan)," he said. "It could have been a consortium, but I don't think it was a consortium that was put together in this country."