DHAKA -- The death toll from Monday's crash of a Bangladesh Air Force training aircraft hit 31 on Tuesday, the Inter Service Public Relations of the Bangladesh Army said in a statement.

It said 165 people, mostly students, were undergoing treatment at different hospitals as the plane crashed onto a school and college campus.

Most of the victims are children, and the other two victims include the aircraft's pilot and a female schoolteacher, Md Sayedur Rahman, special assistant for health and family welfare for the chief adviser of the interim government, said earlier at a press briefing.

The Bangladeshi government is observing a national day of mourning on Tuesday following the jet crash. As part of marking the day, the national flags have been flown at half-mast at all government, semi-government, autonomous bodies, and educational institutions across the country, as well as at Bangladeshi missions overseas.

Bangladeshi interim government's Chief Adviser Muhammad Yunus expressed deep shock and sorrow at the casualties, assuring of an investigation into the matter and proper treatment to the injured.

The government has asked all public and private hospitals to provide free treatment to those who were injured in the crash.

A funeral parade was held Tuesday afternoon for flight Lieutenant Towkir Islam Sagar, who was piloting the aircraft.

According to the ISPR, the Bangladesh Air Force aircraft involved in a routine training flight took off from the A.K. Khandaker Air Base in Kurmitola, Dhaka, at 1:06 p.m. local time on Monday and crashed shortly later into the two-storey school building.