Thai authorities say they're making progress in their investigation into Monday's bombing in central Bangkok and that the city's security situation has stabilized.

Still, the authorities on Saturday called on citizens to be alert for suspicious packages and not to spread rumors on social media.

Col. Winthai Suvaree, a spokesman for Thailand's ruling junta, also said closed circuit television was used to learn the transportation route the suspected bomber took to and from the site of the attack, which killed 20 people.

Meanwhile, new surveillance video has surfaced that may be related to a second blast Tuesday at Bangkok's Chao Phraya River. Police say they've reached no conclusions about the footage, which shows a man kicking a package into the water, but are seeking him for questioning.