Afghan officials say a Taliban suicide car bombing has killed at least 26 people and wounded 41 others in the capital, Kabul.
The July 24 attack came as a presidential spokesman said the militant group also killed 35 civilians in an attack on a hospital in central Ghor Province over the weekend.
The deadly attacks came amid a surge of violence in Afghanistan, where the United Nations says more than 1,700 civilians have been killed this year.
The Taliban said in a statement that the bombing targeted two minibuses belonging to the National Directorate of Security (NDS), the country's spy agency, and claimed to have killed 37 personnel.
However, the government said their intelligence staff never travel in minibuses.
There were conflicting reports on the death toll.
Reuters quoted a senior government official speaking on condition of anonymity as saying the death toll stood at 35, while The Guardian cited unnamed officials reporting at least 38 dead.
Afghan presidential spokesman Shah Hussain Murtazawi said 26 were killed and 41 wounded in the Kabul attack.
At a press conference, Murtazawi also said the Taliban killed 35 people in the hospital attack in Ghor's Taywara district, captured by the Taliban over the weekend.
Murtazawi said all the victims were civilians, without specifying if they were patients or staff.
"This is a cruel crime against humanity," he added.
EU spokeswoman Maja Kocijancic said the "targeting of civilians, particularly doctors and patients in a hospital, is a clear breach of international humanitarian law."
The Taliban denied the claim and reports that they had burned down the hospital, although a spokesman said parts of the building were damaged in clashes with government forces.
Witnesses said the Kabul attacker appeared to have rammed into a bus. Shattered glass from nearby buildings was scattered over the roadway after the blast.
Danish said the bus was badly burned. He could not confirm if the occupants were all government employees.
In a statement, the Interior Ministry called the attack a "criminal attack against humanity."
Afghan President Ashraf Ghani condemned the bombing. "Once again, these terrorist are attacking civilians and targeting government staff," Ghani said in a statement.
The UN Assistance Mission in Afghanistan (UNAMA) also condemned the attack and urged restraint.
“I am personally outraged by all attacks against civilians,” said Pernille Kardel, the UN Secretary-General’s Deputy Special Representative for Afghanistan and acting head of UNAMA. “The detonation of another large suicide device in a busy, civilian-populated area is egregious, cowardly and bereft of humanity.”
The attack came as Hazaras, a Shi'ite ethnic minority in predominantly Sunni Afghanistan, planned to hold a demonstration to mark the one-year anniversary of twin bombings that killed more than 80 people and wounded 230 others, most of them Hazaras.
But the protesters had agreed to delay the demonstration over security fears and after meeting with Ghani on July 23, a presidential statement said.
The bombings on July 23, 2016, were claimed by the Islamic State (IS) extremist group.
Police cordoned off the scene of the July 24 blast, located near the residence of Mohammad Mohaqiq, the deputy to Afghan Chief Executive Abdullah Abdullah. A spokesman for Mohaqiq said he was not injured.
The July 24 blast adds to the unrelenting violence in Afghanistan, where at least 1,662 civilians were killed in the first half of the year, according to the United Nations.
It was also the 10th major attack this year in Kabul, which has accounted for at least 20 percent of all civilian casualties in Afghanistan in 2017.
The Taliban has launched a series of attacks around the country in recent days, prompting clashes in more than half a dozen provinces.
On July 23, the Taliban overran two districts in northern and central Afghanistan.
There was also fighting reported in Baghlan, Badakhshan, Kunduz, Kandahar, Helmand, and Uruzgan provinces, according to officials.