LINCOLN, Neb. (AP) — Nebraska Gov. Pete Ricketts has joined 26 other Republican governors in a letter to President Barack Obama expressing concerns about federal screening of Syrian refugees who want to enter the United States.

The letter released Friday calls for a review of the process refugees undergo before they’re allowed into the country.

Ricketts and other governors have raised concerns following the Nov. 13 attacks in Paris that killed 130. The attacks stoked fears that terrorists might use refugees fleeing from Syria as cover to sneak across borders.

Ricketts has also urged state resettlement organizations not to accept Syrian refugees until federal security procedures are examined.