SANAA (AFP) - Gunbattles raged Wednesday on the streets of Yemen's capital, killing 39 people, witnesses said as a truce between security forces and tribesmen collapsed, residents fled and embassies bolted their doors. A medic at Jumhuriya hospital said 37 people, most of them combatants, were killed in overnight clashes in Sanaa, while an AFP photographer said the bodies of two other tribesmen were taken to Al-Ulum hospital during the day. Heavy fighting ensued on Wednesday, prompting Kuwait to withdraw its diplomatic staff from the city, one day after Italy closed its embassy on concerns of escalating violence following threats against European missions. US Secretary of State Hillary Clinton said Wednesday Yemen's conflict will not end unless President Ali Abdullah Saleh and his government make way for the opposition to begin a political transition. Clinton repeated strong US backing for proposals by Yemen's wealthy Gulf Arab neighbors that would see Saleh leave office in return for a promise of immunity from prosecution. Saleh has balked at signing them. "We cannot expect this conflict to end unless President Saleh and his govt move out of the way to permit the opposition and civil society to begin a transition to political and economic reform," the chief US diplomat said. The fighting between tribesmen loyal to Sheikh Sadiq al-Ahmar, who heads the powerful Hashid federation, and security forces loyal to embattled President Ali Abdullah Saleh broke out in the city on Tuesday. It ended a truce announced on Friday, after a week of fierce clashes that erupted when Saleh warned of a civil war as he refused to sign a Gulf-brokered plan for him to give up office as demanded by protesters. Ahmar had in March pledged his support for protesters who have been demonstrating since January for the departure of Saleh, who has been in power since 1978. The defence ministry's news website said tribesmen had on Wednesday occupied a building near the presidential palace, in the south of Sanaa. The guns fell silent on Wednesday afternoon, but it was unclear how long the lull would last as dozens of armed tribesmen could be seen in the streets of Al-Hasaba, where Ahmar's home is located. Residents had reported street fighting took place throughout the night in Al-Hasaba, an area in the city's north. "We heard the sound of ambulances evacuating the wounded throughout the night," one resident of Al-Hasaba told AFP. One veiled woman, who gave her name as Umm Ahmed, said as she fled from Al-Hasaba with her five children that she was returning to her village. The group was carrying plastic bags filled with clothes. Most shops were closed in Sanaa, and there were long lines at petrol stations. Witnesses said reinforcements from the Republican Guards, an elite unit loyal to the president, had been sent to Al-Hasaba. A fourth army brigade camp located near the state television and radio headquarters was targeted by rockets, as was the interior ministry headquarters, witnesses said., meanwhile, said government forces "regained control of a number of public buildings," without specifying which ones. The website had said on Tuesday that Ahmar's tribesmen had seized both the headquarters of the ruling General People's Congress and the main offices of the water utility.