• A roadside blast in northern Afghanistan kills at least seven people.
• Petroleum firm employees aboard a bus were murdered.
• It’s unclear who was behind the attack.

A roadside blast in northern Afghanistan has killed at least seven people, local officials say.

Local officials say petroleum firm employees aboard a bus were murdered in the 7am bomb in Mazar-i-Sharif on Tuesday.

“The bomb was in a roadside cart. Asif Waziri of Mazar-i-Balkh Sharif’s police said it exploded as the bus arrived.

In the northern Balkh province, the town of Hairatan near the Uzbek border has rail and road connectivity to Central Asia.

It’s unclear who was behind the attack, which comes amid Taliban claims to provide security to Afghanistan after decades of strife.

The Taliban regime returned to power in August 2012 after U.S.-led foreign soldiers withdrew from Afghanistan.

Last month, a blast in Aybak, Samangan province, near Balkh, killed 19 and wounded 24.

In May, nine people died in explosives in Mazar-i-Sharif, while two died in a mosque attack in Kabul.

ISIL (ISIS), the Taliban’s major enemy in Afghanistan, claimed Mazar-i-Sharif but not Kabul.

In October, a suicide bomber killed four at Afghanistan’s interior ministry mosque.