NAIROBI, Kenya (AP) — A massive security operation is in place to protect President Barack Obama during his visit to Kenya, which has been frequently targeted by al-Shabab militants based in neighboring Somalia.

Ahead of Obama's arrival Friday evening, large numbers of security forces have been deployed in the Kenyan capital of Nairobi. Several U.S. military aircraft, part of Obama's security detail, have been spotted flying around the city in recent days.

Major roads will be closed for long periods over the weekend and aviation authorities say the international airport will be closed at times coinciding with Obama's landing and his departure on Sunday for Ethiopia.

Safaricom, a mobile network operator, warned in a statement of temporary service disruptions because of security measures surrounding "the most protected individual in the world."