The United Nations Refugee Agency (UNHCR) has warned Kenya not to expel Somali refugees in response to al-Shabab’s massacre of students.
Kenya has given UNHCR three months to close the the Dadaab refugee camp, which houses 350,000 Somali refugees.
The Kenyan government believes al-Shabab militants who killed 148 people at Garissa University hid in the camp.
The agency warned that the camp’s closure would have “extreme humanitarian consequences.”
Dadaab is just 100km (62 miles) from Garissa, where the killings earlier this month led to outrage and shock across the country.
The government has promised to crackdown on the Somali militant organisation, including those who it with provide support within Kenya.
Kenyan Deputy President William Ruto said on Saturday that unless UNHCR closed Dadaab within three months, Kenya would relocate the refugees.
As well as demanding the expulsion of hundred of thousands of Somalis within the camp, he also announced that Kenya had started building a 700km (440 mile) wall along the entire length of the border with Somalia.
Dadaab was set up in 1991 to house families fleeing conflict in Somalia, and some people have been living there for more than 20 years.
UNHCR says it is not possible for Dadaab residents to return home safely.
The 1951 UN Convention on Refugees, which Kenya ratified in 1966, stipulates that countries must not forcibly return refugees to countries where they may be at risk.
UNHCR spokeswoman Karin de Gruijl said the decision to close the camp “would have extreme humanitarian and practical consequences”, and that the agency was willing to help law enforcement within the camp to combat the threat of al-Shabab.
The Islamist group has vowed a “long, gruesome war” against Kenya.