article_snippet.sent: Even with a wall, militants could arrive by sea to coastal towns in Kenya that have been Islamist strongholds.
article_snippet.sent: The border crosses through remote areas, and many Somalis have fled many Somalis south to Kenya.
article_snippet.sent: Garissa, for example is populated by mainly ethnic Somalis.
article_snippet.sent: But Kenyans also cross north into Somalia, some to fight for Al-Shabaab, then Kenyans return home to help whip up fervor with Al-Shabaab Kenyan affiliate al Hijra, CFR has said.