Witnesses told the press that car loaded with explosives was driven into the wall surrounding the compound and there was an ongoing gun battle.
A police official said that gunfire was coming from inside the building.Al-Shabab militants often launch attacks in the city.
Last month, the al-Qaeda-linked insurgents were behind a two-day siege at a hotel in Mogadishu.
Some reports say the latest attack began with two large blasts.
No group has said it carried out the attack, but Somalia’s al-Qaeda-linked al-Shabab rebels have previously used car bombs to initiate attacks on fortified buildings.
The rebels oppose the country’s internationally-backed government and the African Union forces supporting it.
