Bombs hit two buses taking Afghan government workers to their ministries in the capital Kabul today and at least 40 people were wounded, government officials said.
Violence by Taliban insurgents has surged in Afghanistan this year to its worst level since the militants were ousted in 2001 but most of the bloodshed has been in the south and east.
Attacks in Kabul are rare but yesterday two similar bomb attacks wounded about 10 people.
Today, an Afghan army bus was hit by an explosion in the centre of the capital as it was travelling to the Ministry of Defence during the morning rush hour.
"Three Ministry of Defence workers were wounded," army officer Mohammad Omar Zadran told reporters at the scene. "There were some civilian casualties too."
A security official said a push cart had exploded as the bus was passing.
The bus veered off the road after the blast. It and some small shops were set on fire.
A young man with cuts on his face, Khoja Mohammad, said the blast went off just as he left his house. He said several people on the bus and several passers-by had been hurt.
In the north of the city, a Commerce Ministry bus was hit by a similar blast. A policeman at the scene said one person had been killed and three wounded but the commerce and interior ministries said four people had been wounded.
"A cart blew up and four Commerce Ministry employees were wounded," said Interior Ministry spokesman Yousuf Stanizai.
There was no immediate claim of responsibility.