* Nationalities of dead have not been made public
* Afghan official says crash due to technical problems
* Number of foreign forces casualties falling (Adds UK government statement that helicopter was British)
KABUL, April 26 (Reuters) - Five service members were killed when a British helicopter crashed in southern Afghanistan on Saturday, the NATO-led coalition forces and the British Ministry of Defence said.
An Afghan official said the helicopter carrying soldiers from the International Security Assistance Force (ISAF) had crashed due to technical problems.
"ISAF is still in the process of reviewing the circumstances to determine more facts," ISAF said. It did not provide details of their nationalities.
A spokesman for Kandahar Governor Tooryalai Wesa confirmed the crash occurred near Kandahar City.
"Today at 11 am (0630 GMT) an ISAF helicopter crashed due to technical problems in Takhteh Pol district. As a result five ISAF soldiers were killed," spokesman Dawakhan Minapal said.
In London, the Ministry of Defence said the helicopter was British but did not elaborate on the nationalities of the dead.
"We can confirm that a UK helicopter crashed in southern Afghanistan today," the ministry said in a statement. "The incident is under investigation and it would be inappropriate to comment further until families have been notified."
Foreign forces casualties have fallen in the past few months, as U.S.-led forces start to wind down operations ahead of a year-end deadline to leave Afghanistan.
The United States has been at odds with President Hamid Karzai who has refused U.S. entreaties to sign a bilateral security agreement that would permit about 8,000 U.S. troops to remain in the country after the formal U.S. withdrawal at the end of the year.
The leading contenders to replace Karzai have, however, said they will sign the agreement to allow the small contingent of U.S. forces to stay in the country for counter-terrrorism and Afghan training purposes.
Since the start of the year, nearly twice as many foreign civilians have been killed in attacks this year compared to foreign troops. At least 24 foreign civilians, including doctors and journalists, have been shot or killed in bomb attacks. (Reporting by Jeremy Laurence; Additional reporting by Ismail Sameem in Kandahar and Stephen Addison in London; Editing by Kim Coghill and Raissa Kasolowsky)