A Bangladeshi military training aircraft crashed into the campus of a school in Dhaka, killing the pilot and at least 19 others, mostly students, officials say.

Hundreds of students gathered outside the smouldering remains of a school in the Bangladeshi capital on Tuesday to demand answers after a military jet slammed into the campus, killing dozens of children.

At least 25 children were among the 27 people killed when a Bangladesh Air Force plane crashed into a college and school campus in the capital city of Dhaka on Monday.