In a BBC interview, Mrs Sirleaf said the rise of militant groups - such as Boko Haram in Nigeria and al-Shabab in Somalia - was very disturbing.

She also mentioned recent attacks by Ansar Dine militants in Mali.

The president added that Liberia would lead a campaign to try to contain the menace.

Mrs Sirleaf said that she would now be urging countries which manufactured weapons to sign a treaty to stop arms proliferation.

She was speaking on the sidelines of an African Union summit in the Ethiopian capital, Addis Ababa.

The meeting earlier called on the UN Security Council to intervene in the ongoing conflict in Mali.

Tuareg rebels and the Islamists took control of northern Mali after a coup.

The army seized power in Mali in March, accusing the elected government of not doing enough to halt the Islamist groups.

But the rebels took advantage of the army's disarray to seize the whole of the north - an area the size of France.