Repatriation is the best solution for hundreds of thouands of Somali refugees that Kenya’s government says have become a security liability, the U.N. refugee agency chief said Monday, but he called Kenya’s time frame for the move “very short” to ensure a safe, voluntary return.

Filippo Grandi spoke after visiting the sprawling Dadaab camp. Kenya says 328,000 Somali refugees there must go home by November.

The refugee chief said the refugees may need support for six months to a year, as much of war-torn Somalia lacks the infrastructure to convince them to voluntarily go back home.

Most of the areas in the East African country the refugees came from are still insecure, Grandi said. He said Somalia already has 1 million people displaced inside its borders.

“We don’t want to help people go back and then they become internally displaced; otherwise, it’s just transferring the problem from one place to another where, by the way, it is more difficult to help them,” he said.

“To create infrastructure in Somalia will take years, but we have worked in many situations in the world where you can do some quick fixes so that some initial activities can start, and that will go a long way in ensuring the sustainability of returnees,” Grandi said.

President Uhuru Kenyatta asked the U.N. refugee agency to come up with a plan for the repatriation, Grandi said. He said a committee including the foreign ministers of Somalia and Kenya and representatives of his agency will meet to talk to discuss it.