A suicide bomber has attacked a United States military convoy in southern Afghanistan wounding four American soldiers, US officials say.
A US helicopter lands at the site to carry the wounded soldiers
But they say reports that five US soldiers were killed are wrong.
The Taleban say they carried out the attack, west of the city of Kandahar.
Thirteen US troops have died in Afghanistan since March in an upsurge of violence blamed on the remnants of the country's ousted Taleban regime.
There are concerns that insurgents aim to destabilise parliamentary elections due in September, the BBC's Roland Buerk in Kabul says.
The attack happened when the convoy was moving on the main road west of Kandahar.
US military spokeswoman Lieutenant Cindy Moore said "four US soldiers were hurt and evacuated for treatment".
Taleban spokesman Mullah Abdul Latif Hakimi told the AFP news agency: "A mujahideen brother of ours carried out a suicide attack using a station wagon vehicle and crashed into a three-vehicle convoy of the Americans."
Mr Hakimi said the bomber was a resident of Kandahar and destroyed the middle of the convoy by driving his car into it.
The scene of the blast - just outside the troubled city - was immediately sealed.
Correspondents say that suicide attacks are unusual in Afghanistan.
The few that are carried out are believed to be the work of groups linked to al-Qaeda or other foreign militants accused by the government of trying to derail parliamentary elections due in September.
On 1 June, at least 20 people died in a suicide bomb attack on a mosque in Kandahar.
About 40 others were hurt in the blast, the worst act of violence Afghanistan has seen this year.