Bombs killed four Afghans, including two women, on Saturday as the country marked a national holiday, officials said.
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," provincial spokesman Abdullah Hemat told AFP.
A roadside bomb in the Nahri Sarraj district of neighbouring Helmand province killed two women and wounded two others, the governor's spokesman 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 United Nations 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 September 9, 2001.