Sources: Yemeni president Saleh has collapsed lung, burns over 40%

Yemeni President Ali Abdullah Saleh suffered burns on 40% of his body and has a collapsed lung, U.S. government officials briefed on the matter said, as the fate of the embattled leader -- and whether he will return to the conflict in Yemen -- remains uncertain.

Saleh was injured Friday from an attack at a mosque in his presidential compound and is seeking treatment in Saudi Arabia. An Arab diplomatic source with knowledge of Saleh's condition says one shrapnel wound is 7 centimeters (2.75 inches) deep.

According to Western diplomats, the attack came from a bomb. Yemeni investigations are "focusing on what happened inside the mosque," not a rocket or mortar attack, the diplomats said Monday. One diplomat said the bombing was not a suicide bombing and that the Yemeni investigation "is still ongoing."

But last week, a Yemeni official who asked not to be named told CNN that Saleh was in the mosque when two "projectiles" were fired during Friday prayers. Clashes between government and tribal forces have raged for weeks in Yemen, where thousands of protesters have been pressuring Saleh to give up power since January.

The fighting erupted when Saleh balked at a deal with the opposition that would have eased him out of office in 30 days. Early Tuesday, the fiercest clashes since anti-government protests began in the southern city of Taiz continued through the night, witnesses said. They cited heavy gunfire near the Republican Palace, which is less than two miles from the city's Freedom Square -- a focal point of anti-government protests.

The witnesses did not want to be identified, citing fear for their safety. The goal of the anti-government gunmen was to protect the anti-government demonstrators, who have repeatedly come under fire from security forces during the past two months. Last week, Yemen's government faced condemnation from the United Nations and others for the killing of as many as 50 anti- government demonstrators in Taiz. Yemen's largest opposition bloc has vowed to prevent Saleh from returning.

 "The Yemeni people will do all in their power to not allow Saleh to re-enter the country," Joint Meeting Parties spokesman Mohammed Qahtan said Sunday. One of the U.S. government officials said Monday he can't imagine the Saudis letting him go back. He said it is critical that the Saudis press Saleh to accept a Gulf Cooperation Council deal offering him immunity in exchange for stepping down.

 However, Saudi state-run Ekhbariya television reported Monday that Saleh had undergone two operations in Saudi Arabia and would return to Yemen after he recovers. Christopher Boucek, a Middle East expert at the Carnegie Endowment for International Peace, said he doubts Saleh will return to lead Yemen. "I can't think that President Saleh is going back to Yemen to be president," Boucek said.

 "The regime still maintains that he will return, and they say he's going to return within days, if not weeks. But there's really no option I see for how he can go back and still be president."