Iraq Fortifies Syrian Border to Keep Out Islamic State Militants

Fighters flee shrinking domain, spurring Baghdad to seal off the frontier

Isabel Coles and

Ghassan Adnan

Jan. 31, 2019 8:00 a.m. ET

BAGHDAD—As U.S.-backed forces close in on Islamic State’s last territory in Syria, some militants are fleeing to Iraq—using longstanding smuggling networks and posing as nomadic shepherds to slip through the border, according to Iraqi officials.

Iraq has rushed to reinforce its Syrian frontier amid concerns that Islamic State members will regroup here and threaten the country’s security, military officials said. In recent weeks, the officials said, Baghdad—which fought a yearslong, devastating war to oust Islamic State from...