While regional leaders are gathered in the city to discuss their coordinated offensive against the al-Shabab militant group, mortar shells have exploded in Mogadishu, the capital of Somalia.
The presidential palace is closely guarded, and the four shells struck nearby areas.
There have been no reported casualties.
Following recent military successes by the Somali government against the Islamist militants, the leaders of Kenya, Ethiopia, and Djibouti will meet there on Wednesday.
Al-Shabab still controls large areas of Somalia and is continuing to carry out regular attacks.
But they have lost territory since the government, backed by US and African troops, launched a new offensive last August.