AFGHAN intelligence officials have thwarted a plot to assassinate US Ambassador Zalmay Khalilzad and arrested three Pakistanis armed with rocket propelled grenades and assault rifles, a spokesman for President Hamid Karzai said yesterday.

Afghan intelligence agents have scuttled a plot to assassinate outspoken US Ambassador Zalmay Khalilzad, swooping down on a station wagon carrying three Pakistanis armed with Kalashnikov rifles and rocket-propelled grenades, officials said today.

Four people were killed and at least 71 injured when police opened fire on hundreds of student protestors as they rampaged through an Afghan city.