Yemeni President Ali Abdullah Saleh was more seriously injured in an attack than previously thought, US officials say.
The president is receiving treatment in Saudi Arabia after the rocket attack on his palace in Yemen's capital, Sanaa.
The unnamed officials say Mr Saleh suffered burns to 40% of his body and has bleeding inside his skull, the BBC reports.
The 69-year-old has not been seen since Friday's attack when rockets struck his presidential palace, killing seven people and wounding senior officials in what officials said was an assassination attempt.
The country's acting leader, Vice-President Abd-Rabbu Mansour Hadi, has said Mr Saleh intends to return within days.
Mr Saleh, who has ruled since 1978, has refused to leave office despite protests and a tribal uprising which has brought the country to the brink of civil war and resulted in more than 350 deaths.
Meanwhile, fresh clashes were reported in the southern Yemeni cities of Taiz and Zinjibar.
Military officials said they had killed 30 people they described as militants in Zinjibar, including one whom they said was a senior local al-Qaeda leader.
Government officials routinely blame violence in the country on al-Qaeda in the Arabian Peninsula, the BBC says.