The engineers were in good health and the other captives would also be released soon, according to the district governor in the area where the hostages were taken.
"Eight Turkish engineers were kidnapped recently in Afghanistan when their helicopter crash-landed. Thanks to the efforts of MIT (Turkish intelligence), four of them were handed over to us and are safe," Erdogan told a rally in Istanbul.
A Russian, a Kyrgyz and an Afghan were kidnapped along with the eight Turks on April 21 after the crash-landing of their helicopter in Logar, a Taliban stronghold south of the capital Kabul.
"Four Turkish nationals were freed in a remote area of Nangarhar province this afternoon. They were handed over to a Turkish delegation," Hamidullah Hamid, the district governor of Hazra in the eastern province of Nangarhar, told AFP.
"They were freed after the efforts and mediation of tribal leaders. The Taliban told the tribal leaders that they would free the rest of them in the near future. They are all in good health."
The Taliban were not immediately reachable for comment.
The seizure was the largest abduction of foreigners in almost six years and highlighted Afghanistan`s continuing insecurity as NATO combat troops prepare to pull out next year.
The last time a major group of foreigners was abducted in the country was in July 2007, when the Taliban seized 23 South Korean church volunteers travelling through the south by coach.
The militants killed two men before releasing the rest, reportedly in return for ransom payments.
The Taliban were ousted from power in 2001 by a US-led invasion and have been battling Afghan and foreign troops ever since.
Attacks by them and other insurgents rose 47 percent in the first quarter of this year compared to January-March 2012, according to figures from the Afghanistan NGO Safety Office.
NATO member Turkey has around 1,850 non-combat soldiers in Afghanistan, mainly in Kabul.(*)
Editor: Heru Purwanto
Copyright © ANTARA 2013