SANAA, Sept 15: A Yemeni court on Sunday jailed three Al Qaeda militants to between one and seven years after convicting them of plotting to assassinate President Abdrabuh Mansur Hadi and the American ambassador.

The same Sanaa court specialising in terrorism cases freed a fourth defendant held on similar charges based on time already served in prison.

The defendants were accused of conspiring to carry out a suicide attack against Hadi using a vehicle laden with explosives, according to the charges read out by presiding judge Hilal Mahfal.

But the suicide bomber who was to launch the attack was instead assigned to a different operation by an Al Qaeda leader.

Instead he blew himself up on May 21, 2012 in a square in central Sanaa, killing nearly 100 soldiers taking part in a military parade marking the anniversary of Yemeni unification in 1990, Mahfal said.

It was the largest such bombing in Sanaa since Hadi, who had repeatedly vowed to battle Al Qaeda, came to power in February 2012.

The defendants were also monitoring the movements of US Ambassador to Yemen Gerald Feierstein “to prepare to assassinate him,” according to the charge sheet.

Yemen is the ancestral home of Al-Qaeda founder Osama bin Laden and home base of Al Qaeda in the Arabian Peninsula, the network's deadliest franchise according to the United States.

AQAP militants took advantage of a decline in central government control during a 2011 uprising that forced veteran president Ali Abdullah Saleh from power to seize large swathes of territory across the south.

They were driven out in June 2012 and have been increasingly weakened mainly by US drone attacks.—AFP