A Bangladeshi fighter jet crashed into a school in the capital Dhaka on Monday, killing at least 20 people and injuring more than 170 in the country's deadliest aviation accident in decades.

Many of the victims were young students who had just been let out of class when a Chinese-made F-7 BJI aircraft slammed into the Milestone School and College.

An AFP photographer at the scene saw fire and rescue officials taking away the injured students on stretchers, while army personnel helped clear the mangled wreckage.