Somalia's president is ruling out the possibility of holding elections that are due next year, citing security challenges stemming from an Islamic insurgency.

President Hassan Sheikh Mohamud said in a statement that national elections are impossible amid rampant violence orchestrated by the Somali Islamic extremist group al-Shabab.

Mohamud's term expires in August. Opposition parties charge that that his government is taking advantage of poor security to extend its mandate through postponement of elections.

Al-Shabab, which has ties with al-Qaida, has stepped up attacks in recent months, targeting African Union forces, government officials and foreigners.

On Sunday, at least 15 people were killed when a suicide bomber detonated his explosives-laden truck at the upscale Jazeera Hotel in the capital, Mogadishu.