Police said that at 2.45am, a M79 grenade landed near the Democracy Monument on Din Sor Road side, and then at least one M16 assault rifle was used in an attack on anti government protester guards at Khok Wua intersection.
Witnesses said that after hearing the explosion, a white pickup truck passed through Khok Wua intersection where People's Democratic Reform Committee (PDRC) guards were posted, firing at them.
Some 20 persons were reported wounded from the grenade and shooting attacks. They were sent to Bangkok Metropolitan Administration (BMA) General Hospital and Huachiew Hospital.
The BMA's Erawan Emergency Medical Centre later reported that 24 were wounded in the attack, while two were killed.
The two dead men were identified as Narayot Chanphet, 21, from Surat thani and Somkuan Nuankhanai, 51, from Chumphon who were later pronounced dead at Huachiew and BMA General hospitals respectively.
Four persons were still being treated at Huachiew Hospital, while seven remained at BMA General Hospital.