PROVIDENCE, R.I. (AP) — Rhode Island’s U.S. senators are asking President Barack Obama to extend a federal policy allowing Liberian refugees to live in the United States.

Senators Jack Reed and Sheldon Whitehouse joined 14 other senators in a letter urging Obama to extend the March 31 deadline for Liberians to leave the country.

The policy that allows Liberian refugees to live and work in the U.S. must be periodically renewed. In 2011 Obama granted an 18-month extension. The senators’ Monday letter asks Obama for another two-year extension.

Reed says thousands of Liberians who fled their nation’s civil war could be deported if the policy isn’t extended. The Democrat supports legislation that would allow qualified refugees to reside in the U.S. permanently.