Three loud explosions, including the sound of a missile, were heard in the center of the Yemeni capital Sanaa on Wednesday night, residents and a Xinhua reporter said.
"The two explosions were heard at the direction of an old palace of President Ali Abdullah Saleh, while the missile was heard moving above residents' houses towards the sky above the defected army, nearby opposition-backed protest sit-in near Sanaa University," two of the residents and a Xinhua reporter said.
"Some soldiers came to our neighborhood, telling us via load speaker to turn off all lamps before the huge explosions were heard," said the residents.
The expositions were followed by heavy gunshots in Hassaba district between Saleh's forces and armed tribesmen loyal to opposition tribal leader Sadiq al-Ahmar.
One of the resident said that government forces were firing heavy ammunition on the opposition's key satellite television channel called "Suhail", which is owned by one of al-Ahmar's brothers.
Casualties were not immediately known as all roads and byways nearby were blocked by the rivals.
Meanwhile, random bullets fired by gunmen of the tribal leaders, who vowed to support the protesters' demands of toppling the president, killed a military officer and injured up to nine others on Wednesday evening in a the New Radio Military Camp, which is loyal to President Saleh, one of the camp officer told Xinhua.
Fierce gunshots are continuing.