Five women and a child were killed when a bus carrying Afghan government employees was hit by a bomb in the capital, officials said Tuesday.

The blast ripped through the vehicle during evening rush hour in Kabul on Monday, with government ministries giving conflicting casualty figures.

"Unfortunately, five women were killed and 17 wounded in yesterday's attack," Nasratullah Naseri, a spokesman for the telecoms ministry, told AFP, adding that the blast was possibly caused by a "sticky bomb" attached to the side of the bus where women were sat.

The education ministry said three women and a child were killed, while police said five people died.

Civil servants who are mothers often travel to work with their young children, dropping them off at government-run creches.

No one has claimed responsibility for Monday's blast, and there was no comment from the Taliban.

On Tuesday, gunmen with heavy arms attacked a bus carrying students and teachers of Baghlan University in northern Afghanistan.

"A student and the driver were killed, and six teachers were wounded," Abdul Qadir Mahan, dean of Baghlan University, told AFP.

Two blasts ripped through vehicles in Kabul on Sunday, killing three and wounding more than a dozen, police said.

Violence has surged in Afghanistan in recent months -- including a wave of assassinations against journalists, activists and civil servants -- despite peace talks between the Afghan government and Taliban.

The UN Security Council last week "condemned in the strongest terms the alarming number of attacks deliberately targeting civilians in Afghanistan".

The recent escalation in violence comes with speculation rife about the United States' future in the region after a two-decade military involvement in the country.