Last week, Australian police arrested several men of Somali and Lebanese descent after they were suspected of planning to carry out a suicide attack on an army base in the southern city of Melbourne following months of surveillance.

Al-Shabaab, which means "youth" in Arabic, is one of the main insurgent group fighting Somali government forces and African Union peacekeeping forces in Mogadishu.

The movement, which controls large swathes of territory in the south and center of the war-ravaged Horn of Africa country, is accused of having links with Al-Qaida and being behind most of the suicide attacks against government forces and the AU peacekeepers.

Al-Shabaab wants to topple the Somali government and replace it with an Islamic State, implementing a strict form of the Islamic Sharia law, which it imposes in areas under its rule.

    Meanwhile, Al-Shabaab condemned the meeting between Somali President Sheikh Sharif Sheikh Ahmed and U.S. Secretary of State Hillary Clinton, saying the meeting was meant to harm the Somali people rather than help them.

"The U.S. want to use another tactic to harm the Muslim nation so they have sent this woman representing the Pharaoh of today," an Al-Shabaab spokesman told reporters.

President Ahmed and Clinton met Thursday in the Kenyan capital Nairobi after attending a U.S.-Africa economic forum.