Yemeni President Ali Abdullah Saleh was wounded in the back of head when his presidential palace was attacked by shells on Friday, according to a government official.

The official said on condition of anonymity that the president suffered an injury in the back of his head, "his injury is not that serious and not that light."

Four of Saleh's guards were killed and about 10 senior officials were wounded, some of them in critical condition. Noman Duwaid, governor of the capital Sanaa, had one of his hands and one of his legs cut off and Deputy Prime Minister Rashad al-Alimi was seriously injured, the official said, adding that they are all being treated in the 48th Hospital within the Defense Ministry's compound.

Yemeni state-run TV channel reported that "Saleh was slightly injured and has moved to a secure place."

Shells targeted the mosque inside the Presidential Palace compound immediately after Friday prayers. Some government officials said earlier that the rocket was fired from the house of Hamid al-Ahmer, a prominent opposition leader and a brother of Sadeq al-Ahmer, the Sheikh of Hashid tribe coalition, whose tribal loyalists are currently fighting against the government forces in the capital.

An investigation into the attack has been launched, Deputy Information Minister al-Janadi said, pointing out that the scheduled press conference held by Saleh was delayed.

Loud explosions were heard near Hamid al-Ahmer's house in the 50th street as eyewitnesses said that the house was heavily shelled by the army.