"The summit ... agreed to jointly plan and organize a robust operational campaign at the frontline states level, of search and destroy on multiple frontlines aiming at key al Shabab strongholds across south and central Somalia," they said in a joint statement.
The pledge came after Kenya's President William Ruto, Djibouti's President Ismail Omer Guelleh and Ethiopia's Prime Minister Abiy Ahmed met their Somali counterpart Hassan Sheikh Mohamud in Mogadishu to review measures to weaken the Islamist insurgent group.
"The time sensitive campaign will prevent any future infiltrating elements in the region," the communique said, without providing any details about the operation.
The three countries also contribute troops to the African Transition Mission in Somalia (ATMIS), an African-Union mandated peacekeeping force.
The move follows an intensified offensive by Somalia's federal government against the al Qaeda-affiliated group over the past few months.
It has taken back control of several towns and villages in central Somalia with the help of U.S. military, allied clan militias and forces belonging to Somali regional governments.
Al Shabaab, which did not respond to a request for comment, has been fighting since 2006 to topple Somalia's central government and establish its own rule based on its strict interpretation of Islamic Sharia law.
