Speaking Monday at Ohio State University, Somali President Hassan Sheikh Mohamud said the attack on a Kenyan shopping mall shows the Somali-based terror group al-Shabab has become a global threat.

“Today there are clear evidences that Shabab is not a threat to Somalia and Somali people only,” Mohamud said in a visit made in conjunction with attending the United Nations General Assembly in New York. “They are a threat to the continent of Africa, and the world at large.”

Columbus, where OSU is located, is one of the centers of the U.S. Somlai immigrant population, and there is concern that al-Shabab is recruiting among them.

More about al-Shabab:

Q: What is it?

A: An extremist Islamic terrorist force that grew out of the anarchy that crippled Somalia after warlords ousted a longtime dictator in 1991. Its name means "The Youth" in Arabic.

Q: Who is it?

A: Al-Shabab is estimated to have several thousand fighters, including a few hundred foreign fighters. Some of the insurgents' foreign fighters are from the Middle East with experience in the Iraq and Afghanistan conflicts. Others are young, raw recruits from Somali communities in the United States and Europe.

Q: Where is it?

A: Al-Shabab won control of almost all of Somalia's capital, Mogadishu, in 2006 and held large swathes of central and southern Somalia until a United Nations-backed force from the African Union, including soldiers from neighboring Kenya and Uganda, pushed the militants out of the city in 2011. The rebels still control many rural areas where they impose strict Shariah law and stages suicide bombing attacks.

Q: Why is it attacking Kenya?

A: Al-Shabab had warned for two years that it would attack Kenya in retaliation for the country's leading role in sending troops to Somalia in 2011, a move that helped foster Mohamud's government, which is working to return order to the formerly lawless nation.

Q: Is al-Qaida involved?

A: Al-Shabab and al-Qaida in February 2012 announced their alliance, with al-Shabab leader Mukhtar Abu Zubair pledging allegiance to the global terror movement. U.S. officials believe some of the al-Qaida terrorists who bombed the United States embassies in Kenya and Tanzania in 1998 were given refuge in Somalia.