At least five people have been killed and more than 30 injured in a bomb explosion in the former Taleban stronghold of Kandahar, officials say.
Witnesses say there was blood all over the street
Two women and a child were among those killed by the roadside bomb in a busy central shopping area, reports say.
"There was blood all over the street," one witness told the AFP news agency.
The explosion came as US Secretary of State Condoleezza Rice arrived for talks in the capital, Kabul, on her first visit to Afghanistan.
"Two women, one child and two men died," Kandahar security chief General Salim Khan told the AFP news agency.
"Many people were blown up to two or three metres away," a local mechanic was quoting as saying by AFP.
The bomb went off as two vehicles of the international food agency World Food Programme were passing by.
Programme officials have confirmed one of the vehicles was damaged in the explosion, reports say.
Afghan security officials blamed the blast on members of the ousted Taleban regime.
"Of course it is Taleban. Who else could it be?" Kandahar police chief Khan Mohammad was quoted as saying by AFP.
A Taleban spokesman denied the allegation. "We have no enmity with the civilians," Taleban spokesman Abdul Latif Hakimi told AFP.
He said the blast had been set up to discredit the former ruling militia.
US and Afghan soldiers cordoned off the area, which includes shops and businesses.
"Many people sitting outside were seriously wounded," eyewitness Naimat Khan told the Associated Press. "Some people were covered in blood."
AFP also reports that a second explosion took place in a suburb of Kandahar.
"Two simultaneous explosions occurred, one in the centre of the city and one in the western part of the city," Khaled Pashtun, the city's foreign affairs director, told AFP by telephone.
There are no details of any injuries or damage in that explosion.
Afghan President Hamid Karzai said the act was the "work of enemies who wanted to destabilise Afghanistan by any means possible".
Militants owing allegiance to the former Taleban regime or the al-Qaeda group are said to be still active in parts of southern and eastern Afghanistan.
On Wednesday, the chairman of the US Joint Chiefs of Staff, Richard Myers, described the security situation in Afghanistan as "exceptionally good".
He told reporters in the capital, Kabul, that the Taleban were "essentially in disarray".