Afghan President Hamid Karzai says Tuesday's rare sectarian attacks on minority Shi'ites in the country killed at least 80 people, significantly higher than the previously reported figure of 59.

In a speech Sunday in Kabul, Mr. Karzai said he learned of the updated death toll earlier in the day and blamed the bombings on people trying to undermine peace in Afghanistan. In the deadliest December 6 attack, a suicide bomber blew himself up near a Kabul shrine where Shi'ites were marking the holy day of Ashura, while a smaller blast happened near a Shi'ite shrine in the northern city of Mazar-e-Sharif.

Authorities initially put the death toll at 55 in Kabul and four in Mazar-e-Sharif. It was not clear if the 80 deaths reported by Mr. Karzai included people killed only at the Kabul shrine or in both cities.

Pakistan-based militant group Lashkar-e-Jhangvi claimed responsibility for the Kabul attack, which raised fears that Afghanistan could see an eruption of Sunni – Shi'ite violence of the kind that is common in Pakistan and Iraq.

U.S. Ambassador to Afghanistan Ryan Crocker said Saturday he does not expect the Ashura bombings to ignite a sectarian conflict, in part because Afghan Shi'ite leaders have called for calm.

Afghanistan's Sunni militant Taliban movement issued another statement Sunday condemning the attacks.

In other violence, NATO says a bomb attack killed two of its service members in eastern Afghanistan on Sunday. It did not disclose their nationalities.