The capital braced for Phoumi's attack. A last-minute and temporary switch of sides by Colonel Kouprasith Abhay, commander of the Vientiane military region headquartered at Camp Chinaimo on the eastern outskirts, was quickly neutralized by Kong Le, but tension heightened. The Pathet Lao delegation hurriedly left town. More of Souvanna Phouma's ministers disappeared and reappeared. The situation was becoming ungovernable. Souvanna Phouma viewed battle as inevitable, and, accompanied by his ministers Boun Om (Boun Oum's nephew), Tiao Sisoumang Sisaleumsak, and Inpeng Suriyadhay, flew to Phnom Penh on December 9, having delegated his powers to the military. The following morning Quinim Pholsena, the minister of information whom Souvanna Phouma had left behind, flew to Hanoi accompanied by Phoumi Vongvichit, the chief Pathet Lao negotiator, and Lieutenant Deuane Sunnalath, Kong Le's deputy, on a mission to seek Soviet and North Vietnamese military aid, which began arriving the following day on Soviet aircraft.

Phoumi began his attack on December 13. From his command post near the airport, Kong Le had positioned his men at key points on the outskirts, intending merely to fight a delaying action to allow the safe evacuation to the north of his men and their equipment. The regional command post of the Pathet Lao, situated at Na Khang, sixty kilometers north of the capital, disposed of three guerrilla groups but did not take part in the battle of Vientiane. A massive display of firepower by Phoumi's troops resulted in the deaths of 400 to 500 civilians in the town, mostly Vietnamese residents, and the wounding of another 1,000 to 1,500 civilians. Kong Le's troops only lost seventeen killed. Phoumi's armor rolled into town on December 16.

Kong Le retreated slowly northward toward Louangphrabang, while Soviet aircraft parachuted badly needed supplies--rice, salt, sugar, blankets, light arms, ammunition, and radios. With new recruits, his ranks had swelled from 800 to 1,200 men. On December 23, at Phôn Hông, about sixty kilometers north of the capital, Kong Le was visited by Kaysone, who had come to settle the details of distribution of Soviet aid and coordination of Neutralist and Pathet Lao troops in future operations. On January 1, Kong Le's troops took control of the Plain of Jars and Khang Khay after skirmishing with some of the 9,000 Phoumist troops and an equal number of Hmong guerrillas in the vicinity and recovered large quantities of supplies. The following day, the Neutralists occupied Xiangkhoang, and United States advisers and Phoumist troops were evacuated from the Muang Phônsavan airfield.

Quinim and Tiao Sisaleumsak established themselves at Khang Khay and urged Souvanna Phouma, who was in Cambodia, to join them. Souvanna Phouma said that he was still legally prime minister but would resign at once if Phoumi's government were validated in accordance with the constitution. Souvanna Phouma argued that the National Assembly's vote of no confidence on December 11 was not valid because it had taken place in neither the royal capital nor the administrative capital. H218 He regarded the king's dealings with the Revolutionary Committee as beyond the king's authority. When the National Assembly met in Vientiane and voted confidence in the Boun Oum government on January 4, Souvanna Phouma ignored the action.

Data as of July 1994