CNN: Militants with the Islamist group al-Shabaab stormed Somalia's presidential palace in Mogadishu on Tuesday, firing their way onto the grounds after a car bomb blasted the gate, authorities said.

President Hassan Sheikh Mohamud was not harmed, authorities said, but there were conflicting reports on whether the attackers held any part of the palace Tuesday night.

The militants fired their way onto the palace grounds after a car bomb blasted the gate, police officer Elmi Liban said. Somali and African Union troops exchanged heavy gunfire with the militants, a senior Somali security official said.

Al-Shabaab said it was behind the raid, one of several recent Mogadishu attacks for which the al Qaeda-linked group has claimed responsibility as it presses its campaign to turn Somalia into a fundamentalist Islamic state. Interior Minister Abdullah Godah Barre said all attackers eventually were killed.

Somali government spokesman Ridwaan Haji Abdiwali added Tuesday night that the attack was over. But an al-Shabaab spokesman, Abdulaziz Abu Musab, said the group's militants had captured the offices of the President and the prime minister. It wasn't immediately clear if the offices still were being held Tuesday night.