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.

A Bangladesh Air Force fighter jet on a routine training mission experienced a mechanical failure and crashed into the Milestone School and College campus in the nation's capital city of Dhaka Monday. The crash, and the resulting blaze, killed at least 27 people, 25 of whom were children.