A Turkish engineer and a local security guard have been shot dead in southern Afghanistan in an attack officials are blaming on Islamic militants.
A second Turkish worker and another Afghan security guard were kidnapped in the ambush in the Shah Joy district in the province of Zabul.
The two Turkish men were working on a US-funded project to resurface the Kabul-Kandahar highway.
The road has been the target of several recent attacks.
The men were stopped in the early afternoon while driving on road linking the capital to the turbulent south, army commander Naimatullah Khan told the Associated Press.
Another Turkish engineer and the car's driver were abducted, Mr Khan said.
"The Taleban carried out this attack, Afghan soldiers are
combing through the district looking for them," he added.
The governor of Zabul, Kheyal Mohammad Husseini, told Reuters that the Taleban or forces loyal to the renegade warlord Gulbuddin Hekmatyar were behind the ambush.
Foreign nationals working on the highway, a high profile project, have been the target of several attacks.
Two Indian men working on the road were abducted in December last year.
They were released a month later, and the Afghan Interior Minister Ali Ahmad Jalali said the kidnappers were not linked to the Taleban.
Also in December, a Pakistani engineer was killed and an Afghan worker wounded in an incident on the troubled highway, in the province of Ghazni.
Five armed men were arrested in connection with the attack.
In late October 2003, a Turkish engineer working along the road was kidnapped by the Taleban. He was later freed.