Al-Shabaab militants have moved north to semi-autonomous Puntland after being pushed out of central Somalia, Puntland President Abdirahman Farole says.
They are there to strengthen ties with al-Qaeda in Yemen, which lies a short distance across the sea, he told the BBC.
Al-Shabaab, hardline Islamists, merged with al-Qaeda in February.
They are under pressure on a number of military fronts in the south of Somalia - but still mount frequent attacks.
The leader of Puntland says al-Shabaab fighters and commanders have been arriving over the past few days.