The incident is still under investigation, so details are still developing. Here is what NBC News has reported so far on the attack:
Dallas police found bags with explosives after a shootout involving multiple attackers at their headquarters early on Saturday morning. Officials were also locked in a standoff with at least one suspected gunmen who they believed was involved in the earlier attack.
Officials were investigating four suspicious bags that had been “spread out all over police headquarters,” Police Chief David Brown told reporters. Nearby residents were being evacuated, he said.
One bag was found under a dumpster and another beneath a truck in the police headquarters parking lot, Dallas police tweeted. At least one device exploded when a specialized robot tried to move it, police said.