KABUL－A bomb blast inside a mosque in eastern Afghanistan that was being used as a voter registration center killed at least 14 people and wounded 33, officials said.

Habib Shah Ansari, the provincial head of public health, confirmed the toll from the attack, which took place in the city of Khost, the capital of the province of the same name.

Talib Mangal, spokesman for the provincial governor in Khost, said that there was one female among those killed in the attack.

"The blast happened while people were busy with prayers, meanwhile in other part of the mosque people had gathered to get their voter registration cards for the election," he said.

UN Secretary-General Antonio Guterres strongly condemned the attack and sent his deepest condolences to the families of the victims, said his spokesman Stephane Dujarric.

The UN chief extended his solidarity to Afghan citizens seeking to exercise their constitutional rights and take part in the forthcoming parliamentary elections, Dujarric added.

No one immediately claimed responsibility for the attack, but both the Taliban and a local Islamic State group affiliate reject democratic elections and have targeted them in the past. The IS group is not known to have a presence in Khost, but has expanded its footprint into other areas in recent years.

Last month, an IS group suicide bomber attacked a voter registration center in Kabul, killing 60 people and wounding at least 130 others.

Afghanistan plans to hold elections in October, the first since 2014.

The Taliban and the IS group have launched a relentless wave of attacks since the start of the year, killing scores of civilians in the capital, Kabul, and elsewhere. Afghan security forces have struggled to combat the groups since the US and NATO concluded their combat mission at the end of 2014, switching to a counterterrorism and support role.

Elsewhere in Afghanistan, a vehicle carrying shopkeepers on their way to a market struck a roadside bomb in the northern Faryab province, killing seven of them.

Police spokesman Karim Yuresh said another civilian was wounded in Sunday's attack, in an area where both the Taliban and IS are active.

In the eastern Paktia province, a car bomb killed two people and wounded another three. Abdullah Hsart, the provincial governor's spokesman, said the attack late on Saturday targeted Hazart Mohammad Rodwal, a district chief, who was among the wounded. The Taliban claimed the attack.

AP-Xinhua