Story highlights The Dadaab refugee camp is the world's largest, with more than 600,000 people

Kenya will change "the way America changed after 9/11," deputy president says

William Ruto adds that "we must secure this country at whatever cost"

Nairobi, Kenya (CNN) Kenyan Deputy President William Ruto on Saturday gave the United Nations' refugee agency three months to relocate refugees from the Dadaab camp -- the world's largest -- to Somalia, or "we shall relocate them ourselves."

"The way America changed after 9/11 is the way Kenya will change after Garissa," Ruto said in Nyeri, according to a statement from his office.

Al-Shabaab gunmen stormed Garissa University College in eastern Kenya this month, killing 147 people. Kenya's government says that attack was masterminded by senior Al-Shabaab leader Mohamed Mohamud, whose "extensive terrorist network within Kenya" extends into the sprawling Dadaab complex, according to a Kenyan government document given to CNN.

Ruto, who is the second highest-ranking person in Kenya's government behind President Uhuru Kenyatta, said his government has had discussions with United Nations officials about what to do with the camp.