Witnesses in Somalia say warships have fired on a key port town controlled by the Islamist militant group al-Shabab.

The witnesses told VOA the two warships, believed to be Kenyan, began firing at the coastal town of Kismayo early Tuesday. The attack continued after sunrise, with one shell hitting a house and wounding a child.

Al-Shabab militants returned fire with 106-millimeter recoilless rifles.

A spokesman for Kenya's military said he had no knowledge of the incident.

If confirmed, the attack would open a new front against the al-Qaida-allied rebel group.

Last week, African Union and Somali forces began pushing al-Shabab militants out of another key stronghold — the Afgoye corridor located west of Mogadishu.

Officials with AU and Somali forces say they have successfully moved the rebels out of the corridor, which includes a sprawling camp for about 400,000 refugees.

Military officials said al-Shabab rebels were preventing aid organizations from operating in the region.

Reports from southern Somalia indicated on Monday that al-Shabab leaders were mobilizing fighters in the south, including in Port Kismayo.

Al-Shabab is fighting to overthrow Somalia's transitional government and impose a strict form of Islamic law.

Last year, Kenyan and Ethiopian troops entered Somalia to pursue the rebels.