Al-Shabaab fighters have attacked a southern Somali border town controlled by forces loyal to Somalia's transitional government.

The militant Islamist group carried out the attack early Friday on the town of Dhobley, just five kilometers from the country's border with Kenya.

Heavy artillery fighting between the two sides was reported, but there were no immediate reports of casualties.

Earlier this year, African Union troops and Somalia's Transitional Federal Government drove al-Shabab fighters out of Somalia's capital, Mogadishu, but the al-Qaida-linked group is still battling the government and controls large sections of southern and central Somalia.

The United Nations has declared six regions of south Somalia famine zones, most of which are under al-Shabab control. Al-Shabab has banned most foreign aid groups from operating in areas under its control.

The site of Friday's fighting, Dhobley, lies within the semi-autonomous state of Azania, about 100 kilometers from Dadaab, Kenya, which hosts the world's largest refugee camp.

Dadaab currently hosts 440,000 refugees. Conflict and drought in Somalia have sent a surge of refugees to the camp this year, with 150,000 people arriving in the past few months.

The U.N. refugee agency said earlier this month that 1,200 Somalis are crossing into Kenya on a daily basis.

The Horn of Africa is struggling with a severe drought that has left more than 13 million people in need of food aid.