"The deputy intelligence director of Khost province, Muhammad Isa, was killed in a suicide attack by Taliban and al-Qaida today in the morning," Khost military division commander Khial Baz Khan said.
"The body of the bomber is still lying on the explosion site and we are investigating the case," Khan said, speaking via satellite phone from the scene.
Meanwhile, Pakistan based Afghan Islamic Press (AIP), private news service said a lone assailant shot and killed the intelligence official in his car and tried to flee.
"The man was chased by guards and after some distance he blew himself up with a bomb strapped to his body," the AIP quoted a witness as saying.
Isa received five bullets and died on the spot, it said, quoting witnesses.
Taliban claims responsibility
A spokesman for the ousted Taliban regime claimed responsibility for the attack minutes after it had occurred.
"We claim responsibility for the suicide attack involving the deputy intelligence director of Khost, Muhammad Isa. We targeted him because he was in close contact with Americans, providing them with intelligence information"
Muhammad Saif al-Adl,
"We claim responsibility for the suicide attack involving the deputy intelligence director of Khost province, Muhammad Isa," the spokesman, who calls himself Muhammad Saif al-Adl said.
"We targeted him because he was in close contact with Americans, providing them with intelligence information.
"And he was an ex-communist who was the director of the intelligence department under the communist regime in Afghanistan and now he started working for (President Hamid) Karzai's administration," Saif al-Adl added.
This was the third such attack in the past month in Afghanistan.
On 27 and 28 January, two bombers targeted International Security Assistance Force (ISAF) troops in Kabul, killing a British and a Canadian soldier and wounding more than a dozen others.
Taliban sources has claimed responsibility for both attacks and warned more are to come.
Spokesmen for the former regime warned that dozens of bombers, rarely seen in Afghanistan in the past, had infiltrated the city intending to attack foreign targets.