15 April 2013 (13:35 UTC-07 Tango)/04 Jumada t-Tania 1434/26 Farvardin 1391/06 Bing-Chen (3rd month) 4711

Live reporter says almost immediately emergency personnel began blocking access to media.

Video of first explosion makes it clear the explosions took place in the building directly behind the grand stands.  Could be gas explosion, but media speculating terrorist attack.

A nearby bridge has been closed.  Bus service suspended in area.