KABUL, July 4 (Xinhua) -- A roadside bombing killed six soldiers of the NATO-led International Security Assistance Force (ISAF) in southern Afghanistan on Wednesday, an ISAF statement said.

    The six soldiers, together with one Afghan ISAF employee, were killed after their vehicle struck a roadside bomb, the statement said.

    The statement expressed ISAF's condolences to the victims' families.

    It did not tell which province the incident occurred and the soldiers' nationalities.

    However, the Canadian defense ministry said there had been an incident involving Canadian soldiers in southern Afghanistan and it was being investigated, media reports said.

    Some 2,500 Canadian soldiers are operating in the southern Kandahar province, a stronghold of Taliban rebels, as part of ISAF.

    No one has claimed responsibility for the bombing, but Taliban militants have frequently carried out similar attacks.

    About 37,000 ISAF soldiers are being deployed in Afghanistan to hunt down militants and keep security.

    Some 90 foreign soldiers including those from ISAF and the U.S.-led coalition forces have been killed in this volatile country this year.

    Due to rising Taliban insurgency, over 2,600 persons, most of whom were Taliban militants, have been killed in Afghanistan this year.