Kenya has called on the United Nations to close the Dadaab refugee camp housing over 600,000 Somalis in Garissa after a recent deadly attack by Somalia-based al-Shabab militants killed nearly 150 people in the eastern Kenyan town.

The country’s Deputy President William Ruto made the remarks during a speech in the central city of Nyeri on Saturday, saying the clearing of the site – the world’s largest refugee camp – will allow the Kenyan security forces to tackle terrorism within the country.

Nairobi has asked the Office of the United Nations High Commissioner for Refugees (UNHCR) “to relocate the refugees in three months,” said Ruto, adding that Kenya will resettle the camp’s residents on its own should the UN refugee agency fail to do so.

A UNHCR spokesman responded to Ruto’s comments, saying the organization has not received a formal request from the Kenyan government to close the Dadaab camp.

Elsewhere in his speech, Ruto also said Kenya had begun building a 700-kilometer (440-mile) wall along its border with Somalia in a bid to prevent al-Shabab militants from entering the country.

“We must secure this country at whatever cost, even if we lose business with Somalia, so be it,” said Ruto.

The remarks by Ruto come just over a week after al-Shabab militants attacked the Garissa University campus during the early hours of April 2, killing 148 people, mostly students.

Al-Shabab militants have said the attack was carried out in revenge for Kenya’s military operations in Somalia. The group has also threatened more bloodshed.

The militants have been pushed out of Mogadishu and other major cities in the country by government troops and the African Union Mission in Somalia (AMISOM). AMISOM is largely made up of troops from Ethiopia, Uganda, Burundi, Djibouti, Sierra Leone and Kenya.

However, al-Shabab still holds territory in rural areas of the south.