Iraq’s prime minister will seek President Barack Obama’s help to acquire billions of dollars in drones and other U.S. arms to fight Islamic State during a U.S. visit next week, a senior Iraqi official said.

Facing a cash crunch due to a plunge in oil prices and a budget deficit of roughly $21 billion this year, Prime Minister Haidar al-Abadi wants to defer payment for the purchases, said the official who spoke on condition of anonymity.

Abadi is grappling with an insurgency by militants from Islamic State, an al Qaeda offshoot that emerged from the chaos in Iraq and neighboring Syria and seized much of northern and central Iraq last year. […]