A 45-year-old British man has been arrested in the Somali capital, Mogadishu, for suspected ties to al Qaeda, a spokesman for Somalia's president said Tuesday.

The man is not of Somali origin, said Abdirahman Omar Osman, also a senior adviser to President Sharif Ahmed.

Osman said the suspect had come to Somalia without a visa and upon questioning said he wanted to help Islam. Authorities have seized his computer.

A spokesman at the UK Foreign Office said it was aware of the matter and was looking into it.

Al-Shabaab, a militant Islamist group allied to al Qaeda, controls much of southern Somalia and is active around Mogadishu.

It has waged an insurgency against the weak Transitional Federal Government since 2007.