The Taliban claimed the second attack but many officials say it bore the hallmarks of the Haqqanis, who the United States says enjoy safe haven in neighboring Pakistan. "More such attacks will be carried out", the statement said.
The UN Security Council on Thursday welcomed the Afghan government's offer to engage the Taliban in direct peace talks and called on the Taliban to accept it without preconditions.
The latest blast in the series attacks in the war-weary Afghan capital comes after the USA general in Afghanistan said protecting the city was a priority for foreign forces.
As a follow up to Kabul process, I have extended an official invitation to Pakistani Prime Minister to visit Afghanistan.
The attack comes weeks before the start of the spring fighting season which is expected to be more intense this year as militants respond to intensifying U.S. and Afghan air strikes and ground offensives.
Jan Agha said the attacker targeted a "foreign convoy", but was not successful.
"We need to sustain the pressure", he said, adding that the administration is willing to "give it more time, it deserves more time". To harden Kabul, to protect the people of Kabul and the worldwide community that are here ... the Taliban are in the city.
The Taliban claimed responsibility for the blast that hit the Despechari area in eastern Kabul in the morning on March 17.
But James Mattis, the United States defence secretary, said on Tuesday during an unannounced visit to Kabul that the elements of the Taliban are open to talks with the Afghan government.
"The Pakistanis have wanted to appear responsive", the official said on condition of anonymity, sketching out the need for increased pressure.