At least seven people were killed and six others wounded in an explosion in the northern Afghan city of Mazar-e-Sharif on Tuesday.

According to local officials, the roadside explosion took place near the Seyed Abad intersection in the third district of Mazar-e-Sharif and targeted a bus carrying oil company workers from the Haritaan port, Khamma News Agency reported.

"Today at around 7 a.m. a blast took place in ... Balkh on a bus which belonged to Hairatan oil employees," said Mohammad Asif Wazeri, police spokesperson for the northern province of Balkh, adding that at least six people were wounded.

The wounded people, some in critical condition, were shifted to a local hospital, Waziri said, adding that the number of casualties may increase.

"The bomb was placed in a cart by the roadside. It was detonated as the bus arrived," he said.

So far, no group has claimed responsibility for the attack.

Although the Taliban claim to have improved security across the nation since storming back to power in August last year, there have been scores of bomb blasts and attacks – many claimed by the local chapter of Daesh.

At least 19 people were killed and 24 others wounded earlier on Wednesday by a blast at a madrassa in Aybak, southeast of Mazar-e-Sharif.

Later on Friday, Pakistan's charge d'affaires to Afghanistan Ubaid Ur Rehman Nizamani survived an attack on the country’s embassy in Kabul.

On the same day, former Afghan Prime Minister and chief of Hezb-e-Islami party Gulbuddin Hekmatyar also escaped a suicide bombing in the capital Kabul during Friday prayers.