ISLAMABAD, Pakistan (AP) — A bomb attached to a packed minivan exploded in Afghanistan's western Herat province on Saturday, killing at least seven civilians and wounding nine others, Taliban officials said.

No one immediately claimed responsibility for the explosion, but the Islamic State has claimed credit for similar attacks on civilians and the country’s new Taliban leaders elsewhere in the country since the group seized power on Aug. 15.

Saturday's bombing was the first such attack in Herat. Local Taliban official Naeemulhaq Haqqani said investigations were ongoing.

A Taliban intelligence official in western Herat told the Associated Press that the bomb was attached to the van’s fuel tank. He spoke on condition of anonymity as he wasn’t authorized to release the information to the public.

Herat Ambulance chief Ebrahim Mohammadi said the victims — three in critical condition — were transferred to the provincial hospital.

Since their return to power, the Taliban have imposed widespread restrictions, many of them directed at women.

The United Nations Assistance Mission in Afghanistan on Saturday called on the Taliban to find two women rights activists — Tamana Zaryab Paryani and Parawana Ibrahimkhel — who disappeared on Wednesday from Kabul.

“We urge Taliban to provide information on their whereabouts & to protect rights of all Afghans,” UNAMA said in a tweet Saturday. Taliban have denied any involvement in their disappearance.

An eyewitness said that at least ten-armed people claiming to be Taliban intelligence members broke into an apartment Wednesday in Kabul and arrested Tamana Zaryab Paryani and her three sisters.

The women rights activist posted a video on social media shortly before they were taken away, showing them frightened, breathless and screaming for help. She said that Taliban were banging on her door.

Paryani was among about 25 women who took part in an anti-Taliban protest last weekend against the compulsory Islamic headscarf, or hijab, for women.