New York (CNN Business) United Airlines and JetBlue Airways became the first airlines to cut their US flight schedules on Wednesday, as passenger worry about the coronavirus has caused a sharp drop in demand.

While airlines around the world have been making steep cuts in international flights, these are the first set of cuts made to a US flight schedule.

United will ax flights in the United States and Canada by 10% and overseas flights by a total 20% in April from its original international schedule. That includes overseas flights that were canceled several weeks ago. United is looking at similar domestic and international cuts in May.

The moves were disclosed in an email Wednesday to employees made available to CNN. It also disclosed a hiring freeze, a program of voluntary unpaid leaves of absences or a reduced schedule for US employees and a delay of scheduled pay raises for management employees.

The airline plans to cut the schedule "in a way that minimizes the impact on our employees and our operation," according to the email, including reducing frequency of flights per week between two cities or cutting routes with alternative travel options via indirect flights.

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