A Yemeni soldier, who packed explosives under his uniform, blew himself up in the middle of an army battalion in Sanaa killing 96 soldiers and wounding around 300 of the troops.
Medics said that the casualties were being treated in seven different hospitals in the country's capital.
No one has claimed responsibility for the powerful blast which caused panic among residents. The blast was detonated as soldiers from the government's central security forces were rehearsing for an army parade.
Mohammed Nasser Ahmed, Yemen's defence minister, was present in the area when the explosion took place but escaped unhurt.
The suicide attack in Sanaa was the deadliest since President Abdrabuh Mansur Hadi pledged to oust Al Qaeda militants.
