Fresh clashes took place in Yemen\'s capital on Saturday between government troops and opposition fighters, leaving four civilians dead, and up to 21 others injured, witnesses and medics said. The clashes came hours after the United Nations Security Council adopted a resolution calling on Yemeni President Ali Abdullah Saleh to step down. \"Fouad al-Shamiri, a journalist at Sanaa-based independent Al- Saeeda Satellite TV channel, and three other civilians named Ameen al-Bably, Dirham Sariee and Moamar al-Houni were brought dead to the opposition-run Science University Hospital,\" a medic told Xinhua. \"They died of shrapnel wounds after stray shells hit the headquarters of the Al-Saeeda TV channel and a mosque in the war- torn district of Hassaba in downtown Sanaa,\" the medic said on condition of anonymity. \"The hospital has so far received another 21 civilians injured by similar random shelling by the rival forces,\" he added. Witnesses said more than 40 civilian houses in Hassaba have been shelled by artillery and tanks since Friday night. The casualties among the rival forces are unknown, but some opposition media reported that at least one of the opposition rebels was killed. Meanwhile, commander of the defected army Ali Mohsen al-Ahmar who is a half-brother of Saleh, claimed in a statement that \"his special unit tapped a telephone conversation between Saleh and his military leaders, which showed that they gave orders to shell and destroy all sites of his opponents in Hassaba.\" Elsewhere in southern Taiz city, some 200 km south of Sanaa, fresh clashes erupted Saturday between Saleh\'s forces and armed tribesmen, who pledged to protect and defend anti-Saleh protesters since late January, injuring at least four protesters, witnesses and medics said. \"The four protesters were injured by live rounds when the rival forces exchanged gunfire during a march of thousands of protesters in downtown Taiz nearby al-Shaab school,\" one of the eyewitnesses told Xinhua by phone. Doctors at al-Rowda Hospital confirmed that they received the four injured protesters.