​How Kenya upped security for President Obama's visit

NAIROBI, Kenya -- President Obama arrived in his ancestral home Friday and was immediately greeted with a hug from his half-sister Auma.

He then ate dinner with her and other relatives, including his 94-year-old step-grandmother Sarah Obama, known here as Mama Sarah.

Mr. Obama last visited Kenya -- and his late father's village -- as a senator in 2006. But in a sign of the security concerns on the ground, he will not be traveling to that village on this trip.

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President Obama embraces his half-sister Auma upon arrival in Nairobi, Kenya
CBS News

Kenya is on edge because of the continued threat from the al Qaeda-affiliated al-Shabaab. In 2013, terrorists from the group attacked the upscale Westgate Mall, killing 67. Just this April, al-Shabaab targeted Christian students at Garissa University, ultimately killing 148.

Joseph Boinnet runs Kenya's national police force and has overseen the installation of hundreds of security cameras in major cities.

"We started off with about 200," he said. "Now we are working towards putting in place more than 400."

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A security worker monitors feeds from surveillance cameras in Nairobi, Kenya during President Obama's visit
CBS News

Video feeds from Nairobi, Garissa, and Mombasa pour into the agency's modern command center. Security officials receive advice and training from the U.S. State Department.

Boinnet says al-Shabaab is a danger.

"They operate out of Somalia, sneak in and often sneak out," he said. "But we are working very, very hard to fix that problem."

The president's visit is a source of enormous national pride -- one Boinnet and his forces hopes will not be marred by violence.