Both attacks took place in the south after US officials confirmed the withdrawal of extra "surge" troops, deployed largely to the south, was on track, with 77 000 US and 40 000 non-US troops left in Afghanistan.
In Tirin Kot, the capital of Uruzgan province, two tribal elders were killed when a bomb exploded outside one of their homes.
"A bomb placed at the entrance of Malik Abdul Majid's house killed him and another elder and wounded two of Majid's sons," said provincial spokesperson Abdullah Hemat.
A roadside bomb in the Nahri Sarraj district of neighbouring Helmand province killed two women and wounded two others, the governor's spokesperson Farid Ahmad Farhang said.
There was no immediate claim of responsibility but similar attacks are usually blamed on Taliban insurgents fighting to overthrow the Western-backed government of President Hamid Karzai.
The UN says 1 145 civilians were killed in the war in the first six months of this year, blaming 80% of the deaths on insurgents.
Security was stepped up on Saturday as Afghanistan marked 11 years since the death of an iconic anti-Taliban commander two days before 9/11.
Ahmad Shah Massoud helped repel the 1980s Soviet invasion and led the last bastion of resistance to the Taliban in the 1990s before being killed by an al-Qaeda bomb on 9 September 2001.
A teenage suicide bomber struck outside Nato headquarters in Kabul on Saturday, killing six people, including child hawkers, as Afghanistan commemorated the death of Massoud, officials said.
The blast reverberated through Kabul's diplomatic quarter, which is home to many Western embassies, shortly after First Vice President Mohammad Qasim Fahim finished an address to scores of dignitaries at an event mourning Massoud.
"It was a suicide attack that killed six people and wounded five others," said interior ministry spokesperson Sediq Sediqqi
A senior police official speaking off the record gave the same death toll.
"It was a suicide bombing carried out by a young boy. So far there are six dead and five wounded. Most of the victims are young children who gather around Isaf to sell small items to soldiers leaving or getting into the base," he said.
General Ayub Salangi, the Kabul police chief, confirmed four deaths.
"A 16-year-old boy on foot, blew himself up killing four and wounding two, all civilians. There are some children among the dead and wounded," he said.
A spokesperson for Nato's US-led International Security Assistance Force confirmed only a blast and said that there had been no damage to Isaf headquarters or military casualties.
"We're aware of a blast that occurred just outside Isaf headquarters in Kabul this morning," said US Army Major Adam Wojack.
"There are no Isaf casualties. The Isaf compound is secure," he said.