By C. Bryson Hull

NAIROBI, March 18, 2008 - The United States has formally designated Somalia's al Shabaab militants a foreign terrorist organization to increase pressure on what Washington says is al Qaeda's main link in the Horn of Africa nation.

The al Shabaab is the militant wing of the Somalia Islamic Courts Council that took over most of southern Somalia for the second half of 2006, until Somalia's interim government and its Ethiopian military allies routed the group in a two-week war.

The group, whose leader Aden Hashi Farah Ayro survived a U.S. airstrike in January 2007, is thought by security experts to be leading an insurgency that has killed 6,500 people since last year.

The designation put the Shabaab alongside groups such as al Qaeda, Sri Lanka's Liberation Tigers of Tamil Eelam, the Palestinian Hamas group and Lebanon's Hezbollah.

"I hereby designate that organization and its aliases as a foreign terrorist organization," U.S. Secretary of State Condoleezza Rice said in a notice published on Tuesday in the U.S. government's Federal Register.

The designation allows Washington to freeze the assets of any person or group linked to al Shabaab, another tool to go alongside military and intelligence efforts that have led to four U.S. military strikes in Somalia in the last 14 months.

" U.S. financial institutions can get assets of anyone involved and block them and prevent any material support getting to them," said a U.S. official who spoke on condition of anonymity. "We will be reaching out to other governments to get them to implement similar provisions."

Al Shabaab has adopted Iraq-style tactics, including assassinations and roadside bombs and has claimed at least one suicide bombing -- unheard of in Somalia's moderate Sufi Islamic customs.

"VIOLENT, BRUTAL GROUP"

"Al-Shabaab is a violent and brutal extremist group with a number of individuals affiliated with al Qaeda," the State Department said in a statement released in Washington.

"The designation will raise awareness of al-Shabaab's activities and help undercut the group's ability to threaten targets in and destabilize the Horn of Africa region," it added.

Western security officials and diplomats say Ayro trained with al Qaeda in Afghanistan and has provided shelter to al Qaeda operatives involved in 1998 and 2002 bomb attacks in neighboring Kenya.

They say the al Shabaab, under Ayro's command, has been responsible for killing aid workers and journalists, the desecration of an Italian colonial-era cemetery in 2004 and scores of attacks during the insurgency.

That has always been Washington's concern in the absence of an effective central government in Somalia since the ouster of dictator Mohamed Siyad Barre in 1991, and

It was the second time Washington has moved to freeze assets of Somalis on terrorism grounds. Ayro's mentor, Sheikh Hassan Dahir Aweys, was one of 189 people or entities "linked to terrorism" whose assets were frozen by the United States after the Sept. 11, 2001, attacks.

The two are among six members or associates of al Qaeda thought by the United States to be in Somalia.

In New York, U.N. Secretary-General Ban Ki-moon issued a report on Somalia which said there were indications that "international terrorists have sought safe haven in the Hiraan and Juba districts, considered to be the stronghold of (Islamic Courts Union or ICU) extremist elements."

The Security Council will discuss the report on Thursday and diplomats said it would again consider possibly sending a U.N. peacekeeping force, a move supported by South Africa but which permanent council members Britain and France are wary of.

"The security situation remains volatile throughout the country," Ban said.

The United Nations has not itself confirmed the existence of "terrorist cells" in Somalia, but Ban's report raised the concern that "the longer law and order is absent from Somalia, the greater the chance that international terrorists will use its territory as a safe haven." (Additional reporting by Mark Trevelyan in London and Arshad Mohammed in Washington, Editing by Matthew Tostevin and David Storey) (For full Reuters Africa coverage and to have your say on the top issues, visit: http://africa.reuters.com/ )

Source: Reuters