(AP) — Federal aviation regulators are ordering United Airlines to step up inspections of all Boeing 777s equipped with the type of engine that suffered a catastrophic failure over Denver Saturday.

United says it is temporarily removing those aircraft from service. Boeing has recommended aircraft with the engines be grounded pending a decision on inspections.

The announcements came a day after United Airlines Flight 328 had to make an emergency landing at Denver International Airport after its right engine blew apart just after takeoff.

The National Transportation Safety Board said two of the engine’s fan blades were fractured although it did caution that it was too early to draw conclusions about how the incident happened.

We recommended and support suspending operations of the 69 in-service and 59 in-storage 777s powered by Pratt & Whitney 4000-112 engines while the NTSB investigation is ongoing.

Read statement on United Airlines Flight 328: https://t.co/iz1r8QQzkS

— The Boeing Company (@Boeing) February 22, 2021

Federal aviation regulators ordered United Airlines to step up inspections of all Boeing 777s equipped with the type of engine that suffered a catastrophic failure over Denver Saturday. United is temporarily removing those 24 aircraft from service. https://t.co/xn5HW6NLfQ

— The Associated Press (@AP) February 22, 2021