Taliban insurgents gunned down a top official of Afghanistan's Supreme Court as he left his home in Kabul on Saturday, the latest in a spate of strikes by the hardline Islamists on a broad range of targets in and around the Afghan capital.

Heavily fortified Kabul is on high alert after insurgents stepped up attacks in recent weeks, targeting guesthouses, government officials and civilians as most foreign troops prepare to leave the country by the end of this month.

Hashmat Stanekzai, spokesman for Kabul's police chief, said Atiqullah Raoufi was shot by unknown gunmen in western parts of Kabul. Raoufi headed the secretariat of the court.

"As Atiqullah Raoufi was leaving his house, gunmen opened fire and shot him dead," Stanekzai told Reuters, adding that no one has been detained.

The Afghan Taliban, ousted from power by U.S.-backed Afghan forces in 2001, claimed responsibility, but did not say why they had killed him.

The Taliban also shot dead 12 demining workers near the former British base of Camp Bastion in Afghanistan's southern Helmand province on Saturday, opening fire from motor bikes, police said.

Farid Ahmad Obaid, a spokesman for the provincial police chief, said Afghan forces later launched a counter attack, killing four of the Islamist militants and capturing three.

Saturday's shootings come two days after a teenage Taliban bomber targeted a French-run auditorium packed with people watching an anti-suicide bombings play, killing one German national and wounding 16 people. The bombing was a rare strike on a civilian target.

Elsewhere, a roadside bomb targeted a convoy of foreign troops in Bagram district of the relatively peaceful Parwan province north of Kabul on Friday, but caused no casualties, officials said.

The Taliban, seeking to bring down the government of Ashraf Ghani and its Western backers, claimed responsibility for the attack.

On Thursday, a suicide bomber killed six Afghan army soldiers and wounded 11 in an attack on their bus in Kabul.