TEHRAN, Iran, April 26 -- The number of injured from an explosion Saturday at a port in southern Iran jumped to 281, the state-run IRNA news agency reported.

IRNA quoted Mojtaba Khaledi, the spokesman of Iran's National Emergency Organization, as giving the figure.

The blast happened at the Rajaei port just outside of Bandar Abbas, a major facility for container shipments for the Islamic Republic that handles some 80 million tons (72.5 million metric tons) of goods a year.

Social media videos showed black billowing smoke after the blast. Others showed glass blown out of buildings kilometers (miles) away from the epicenter of the explosion.

Authorities have offered no cause for the explosion yet. Industrial accidents happen in Iran, pa...