The death toll from the collapse of an elevated section of the Mexico City metro has risen to 26 after an injured passenger died in a hospital.

A total of 33 victims remain hospitalised, recovering from injuries suffered in the accident.

A total of about 80 people suffered injuries when beams supporting part of the elevated line failed as subway cars were passing over it.

Mexico Metro Collapse
Family members protest demanding justice for the people who died in Monday’s subway collapse (Eduardo Verdugo/AP)

Most of those have been treated and released.

Monday night’s accident was one of the deadliest in the history of the subway, and questions quickly arose about the structural integrity of the mass transit system, which is among the world’s busiest.

Authorities have pledged an investigation into what caused the collapse, and have promised to inspect all the elevated lines and overpasses in the city.