Sri Lanka, April 26 -- A powerful explosion and fire at Iran's largest commercial port has killed at least five people and injured more than 700 others, authorities say.

Mehrdad Hasanzadeh, director of Hormozgan province's crisis management organisation, provided the figures on Saturday during an interview on state television. The previous toll was four dead and more than 500 others injured in the explosion at Shahid Rajaei port, located more than 1,000km (620 miles) south of the capital, Tehran.

Iranian state television said initial reports indicate negligence in the storage of flammable materials at the site.

On Saturday night, the state-run IRNA news agency said that the Customs Administration of Iran blamed a "stockpile of hazardou...