KABUL • The Islamic State in Iraq and Syria (ISIS) has said it was behind an attack in Kabul on Friday, where gunmen opened fire at a political rally and killed dozens of people - the deadliest assault in Afghanistan since the US signed a withdrawal deal with the Taleban.

The attack highlights a glaring lack of security in the Afghan capital, just 14 months ahead of the scheduled withdrawal of all foreign forces. It also calls into question a key element of the US-Taleban deal signed on Feb 29: whether the Taleban can stop militants such as those from ISIS from running amok in Afghanistan after United States forces pull out.

In a statement, ISIS said two brothers had targeted a "gathering of apostates" with machine guns and grenades.

The gunmen inflicted devastating carnage at the crowded event in west Kabul, killing 32 people and wounding 58 others, Health Ministry spokesman Wahidullah Mayar told Agence France-Presse. Interior Ministry spokesman Nasrat Rahimi put the toll at 29 dead, with an additional 61 wounded. He said special forces units eventually killed the two gunmen.

The assault occurred at a commemoration ceremony for Mr Abdul Ali Mazari, a politician from the Hazaras ethnic group - most of whom are Shi'ite Muslims. Several top political officials were at the ceremony, including Afghanistan's Chief Executive Abdullah Abdullah.

United Nations secretary-general Antonio Guterres expressed his "deepest sympathies" to the victims' families. "Attacks against civilians are unacceptable and those who carry out such crimes must be held accountable."

AGENCE FRANCE-PRESSE