Jordan’s King Abdullah has advocated enlisting tribal groups to mount ground attacks to defeat Muslim radicals known as Islamic State militants.

King Abdullah made the remarks in an interview with NHK in Tokyo on Wednesday.

Jordan is part of the US-led coalition staging airstrikes against the Islamic State.

But the king said airstrikes alone are not the answer and that the coalition needs to reach out to local tribes in Syria and Iraq to join the fight against the radical group.

The Islamic State is drawing many fighters from Middle Eastern countries.

The king said many of those new recruits are unemployed and lack hope for the future.

He emphasized the need to develop the region’s economy to prevent the extremist group from bringing more areas under its control.

Refugees from neighboring Syria now account for one-fifth of Jordan’s population.

King Abdullah said the effort to host all the refugees is a tremendous burden. He said foreign aid to both Jordan and the UN High Commissioner for Refugees will cover only about 30 percent of the cost this year. The king urged the international community to extend more assistance.