Days of armed clashes between tribal fighters and government troops have turned the capital Sanaa into a battleground.
Fighting has continued in Sanaa, the Yemeni capital, between forces loyal to the president and those allied to an opposition tribal group.
Much of the fighting has happened in the Hasaba district in the northern part of the city on Thursday, where fighters from the Hashed tribal confederation confront forces loyal to President Ali Abdallah Saleh.
Medics in Sanaa told the AFP that 15 people, including a seven-year-old girl hit by a stray bullet, have been killed in clashes overnight.
Hakim Al Masmari, editor of the Yemen Post, told Al Jazeera that an estimated 2,000 additional fighters “armed and ready to fight” have entered Sanaa as reinforcements to the Hashed tribal confederation, led by Sadeq al-Ahmar.
“We expect [the tribal fighters] to take control of different government complexes [in Sanaa],” Al Masmari said.
Witnesses near Sanaa’s Hasaba distric said they heard several blasts but were not sure of the cause or damage.
Hasaba has been the focal point of armed clashes over the past week that have killed at least 115 people and pushed the country closer to civil war.
“There are very powerful explosions. Sounds like missiles or mortars. May God protect us,” a Hasaba resident said.
After a lull of several hours, large blasts began shaking northern Sanaa and nearby areas late on Wednesday, residents said. There was no immediate report of casualties or damage.
In Taiz, security forces have reportedly opened fire on opposition protesters. More than 50 protesters have been killed by security forces since Sunday.
Witnesses told the AFP on Wednesday that previously unarmed protesters in Taiz have resorted to carrying weapons and have clashed with police.
This week, there have been three main flashpoints in the country – the fighting in the capital, government troops firing on protesters in Taiz in the south and a battle with fighters in the coastal city of Zinjibar.
Residents also reported overnight fighting near Sanaa airport, which was closed briefly last week during skirmishes between Saleh’s forces and Hashed rebels.
Speaking to reporters, Hillary Clinton, the US secretary of state, said, “If it wasn’t obvious before it certainly should be now that [Saleh’s] presence remains a source of great conflict.”