Mogadishu, Somalia, July 9 — A suicide bomber detonated explosives outside the Jaalle Siyaad Military Academy in Mogadishu late Tuesday morning, causing an unknown number of casualties, Somali authorities said.

The blast, which was heard across several neighborhoods of the capital, occurred at approximately 11:20am local time, the Ministry of Defence confirmed in a brief statement.

"A suicide bombing took place at the entrance of Jaalle Siyaad Military College, carried out by a terrorist affiliated with the Khawarij group Al-Shabaab," the ministry said, using a term Somali officials often employ to describe the al-Qaeda-linked militants.

Security forces have launched an investigation into the attack and further details will be shared with the public once the probe is complete, the ministry added.

"The security agencies are conducting thorough investigations, and the official information will be communicated to the public once confirmed, God willing," the statement said.

The area around the academy has since returned to calm, and traffic on the main road in front of the college has resumed, witnesses said.

The attack comes after a relative lull in bombings in the capital, as government forces and allied local militias intensify their military operations against Al-Shabaab in several regions of the country.

The group has frequently targeted military installations in the capital, including past attacks on recruitment centres for new army recruits.

Al-Shabaab has not yet claimed responsibility for Tuesday's bombing.