At least nine people were killed during the assault on the CID headquarters, including four attackers, local police reports.
Earlier, police reported seven dead.
"We have confirmed seven dead including civilians and two militants," Ali Mohamed, a police officer, said as cited by Reuters.
According to police, a car laden with explosives hit the gates of the CID headquarters, clearing entry for fighters who stormed in after the vehicle exploded, Reuters reports.
#Somalia reportedly 2 SVBIED bombings at #Mogadishu Criminal Investigations HQ
— Jasmine Opperman (@Jasminechic00) July 31, 2016
Photos via @Yassinjuma pic.twitter.com/v1l004EtiS
Another bomb attack today in #Mogadishu. Heavy bomb and attack ongoing at the CID HQ. pic.twitter.com/dbOcaLnR8p
— M.Mubarak (@somalianalyst) July 31, 2016
A radical Islamist group al-Shabaab claimed responsibility for the attack, claiming that there is intense fighting inside the headquarters.
Breaking: Alshabab hit Somali police criminal investigation Department in #Mogadishu.
— Ahmed Abdihadi (@AhmadAlhaadi) July 31, 2016
Law enforcement, howver, is unable to give precise information on the death toll.
"It is too early to tell the number of casualties," Reuters quoted a police officer as saying.
BREAKING: Two huge explotions hit by #Mogadishu's CID building, casualties reported, wittness. #Alshabaab #Somalia pic.twitter.com/3500dD6UVS
— Gobanimadoon (@gobonimadoon) July 31, 2016
Less than a week al-Shabaab took responsibility for two suicide attacks on checkpoints near Mogadishu's International Airport, which killed at least 13 people.
MORE PHOTOS of the twin VBIED bombing outside CID Hq #Mogadishu #Somalia #Alshabaab claims responsibility pic.twitter.com/2pIphOvgri
— Yassin Juma (@Yassinjuma) July 31, 2016