TEHRAN, Aug. 15 (Xinhua) -- A plane used for flight training crashed in northern Iran on Saturday, killing two people on board, the semi-official Mehr news agency reported.

    The plane crashed in the city of Karaj, west of Tehran, after taking off from Payam airport at 7:00 a.m. (0230 GMT). The cause of the accident is still under investigation.

    Saturday's accident was the latest one added to the poor air safety record of Iran, which has seen a series of aviation disasters over the past one month.

    On Monday, three people were killed and three others injured in a Bell 205 police helicopter crash in southern Iran. The helicopter was returning from an operation when it crashed in a mountainous region near the city of Kerman on Monday afternoon.

    A technical problem is supposed to be the cause of the crash, according to an official in the Governor General office of Kerman Province.

    Earlier this month, a Boeing 707 passenger plane belonging to Iran's army airlines Saha made an emergency landing at Ahvaz airport on August 3.

    The emergency landing happened ten minutes after its taking off due to technical failure, according to Iran's Civil Aviation Organization. All the 176 passengers on board were safe.

    On July 24, a Russian-made Ilyushin Il-62 plane, which was traveling from Tehran to northeastern city of Mashhad with 153 passengers on board, caught fire and skidded into walls near the runway during its landing in Mashhad.

    In the incident, 16 people were killed and around 30 others on board were injured.

    On July 15, a Russian-made Topolov passenger plane belonging to Iran's Caspian Airlines crashed near northwestern city of Qazvin on its way to Armenia, killing all 168 people on board. It was the worst plane crash in Iran in six years.

    The plane caught fire in midair and ploughed into a farmland 11minutes after its take-off. Officials have attributed the incident to technical problems of the plane.

    The passenger planes crashed in the past one month were either Russian-made timeworn planes or outmoded American aircraft imported to Iran decades ago.

    The long-term sanctions imposed by the United States against Iran have prevented the country from purchasing new aircraft or spare parts from western countries, which are the dominant producers of passenger planes in the world market.

    Experts believe the sanctions undermined safety standards within Iran's civil and military aviation fleet since its aging fleet can only get supplement from the former Soviet countries, and the likelihood of more major air disasters is increasing.

    Iran's prosecutor general claimed last month that sanctions on the country's air industry is a crime against humanity.

    Iran's parliament has urged a ban on the purchase of Russian-made passenger planes, asking the government to avoid purchasing timeworn Russian-made planes.