The presidential palace in Yemen reportedly was hit by shelling Friday as government troops battled with opposition tribesmen in the capital city.
A government official told The Associated Press that President Ali Abdullah Saleh and four top officials — the prime minister, the deputy prime minister, the parliament chief and a presidential aide — were wounded when rockets hit the building.
Yemeni television later said the president was fine.
National Security Council spokesman Tommy Vietor said the U.S. was monitoring reports that Saleh was wounded but could not confirm that he was injured. Vietor said the U.S. is "very concerned" about the escalating violence in Yemen and that the dispute there will be solved only through negotiations.
It was the first time that tribesmen have targeted Saleh's palace in nearly two weeks of heavy fighting with government troops in the capital.
Fears are growing that Yemen may slip into civil war as the long-running protests have so far failed to dislodge the president. Weak governmental authority has already made the country a regional haven for militants.
The White House has dispatched envoy John Brennan to Saudi Arabia and the United Arab Emirates to discuss the crisis in Yemen. Persian Gulf leaders have pressed Saleh to step down, only to see him refuse at the last minute.
Meanwhile, tens of thousands of Yemenis held a mass funeral Friday for 50 people killed in regime-sponsored violence in the capital.
Soon after Friday prayers, witnesses said heavy shelling rocked the commercial neighborhood of Hadda in southern Sanaa. Residents fled to basements for cover.
One witness said the target appeared to be the home of a tribal notable and brother of the tribal leader whose forces have been in a confrontation with by forces loyal to Saleh for two-weeks. The witnesses spoke on condition of anonymity fearing retribution.
In the south, activist Bushra al-Muktari said security forces opened fire on protesters in the city of Taiz. She said two protesters were injured. She reported scattered small rallies across the city after their main protest camp was broken up violently this week.
The city was locked down, and travelers barred from entering the city. Mohammed al-Said said he and his family escaped the violence in Sanaa to Taiz, only to be left waiting on the outskirts of the city since daybreak.
For months, youth-led protesters have sought to peacefully oust Saleh, but their campaign has been overtaken and transformed into an armed showdown between Yemen's two most powerful families, the president's and the al-Ahmar clan. The al-Ahmar family heads the country's strongest tribal confederation, which has vowed to end Saleh's 33 years in power.
Violence in Sanaa escalated to new heights overnight as shelling expanded beyond the neighborhood where al-Ahmar clan chief lives. Troops attacked and burned the headquarters of a private TV station owned by one of the 10 al-Ahmar brothers. A building housing an airline office also was set alight.
Despite the gunfire and shelling, protesters swarmed into a Sanaa main street for Friday prayers and funeral processions. During the Friday sermon, the imam said Saleh was trying to convert the revolt from a popular uprising into a personal conflict between him and the tribal chief Sadeq al-Ahmar.
The president "wants to overturn this revolution and show the world that it is a conflict between al-Ahmar and Saleh," Imam Taha al-Mutawakil told the crowd.
A young man speaking to the crowd said the Friday gathering also meant to show support for the protesters in the southern city of Taiz. "By declaring war on the Yemeni people, Saleh's regime is committing suicide," the man said in a microphone.
The protesters distributed leaflets in the crowd, giving them instructions on how to deal with the recurrent shelling, particularly in the middle of the night. "Keep your cool. Keep the windows open, shut off the gas and water, go to the basement."
NPR's Peter Kenyon reported from Cairo, Egypt, for this story, which contains material from The Associated Press.