WASHINGTON, April 28 (Reuters) - The Federal Aviation

Administration said a series of issues prompted it to

dramatically slow traffic at Newark Liberty Airport on Monday,

prompting United Airlines to divert at least 35 flights

to other airports.

United Airlines, the largest carrier at the airport just

outside New York City, said an FAA equipment malfunction caused

a significant disruption and it expects cancellations and delays

for the rest of the day due to FAA staffing issues.

Flights were diverted to numerous airports on the U.S. East

Coast. Some diversions involved transoceanic flights from Europe

being moved to smaller airports.

The FAA said the issue was first prompted by

telecommunications and radar equipment issues at Philadelphia

Terminal Radar Approach Control, which guides aircraft in and

out of Newark. Both have been resolved, but now there are

staffing issues at Philadelphia impacting flights, the FAA said.

The National Air Traffic Controllers Association had no

comment.

The FAA canceled a ground stop later on Monday afternoon but

hours after the problems began departures for Newark were still

being delayed on average by more than three and a half hours,

while departures were being delayed by an average of 48 minutes.

The FAA last year relocated control of the Newark, New

Jersey, airspace area to Philadelphia to address staffing and

congested New York City area traffic.

It also extended cuts to minimum flight requirements at

congested New York City-area airports through October 2025,

citing air traffic controller staffing shortages.

Under minimum flight requirements, airlines can lose their

takeoff and landing slots at congested airports if they do not

use them at least 80% of the time. The FAA's waiver allows

airlines to fly fewer flights and still retain slots.

The FAA is about 3,500 controllers short of targeted

staffing. A persistent shortage of controllers has delayed

flights and, at many facilities, controllers are working

mandatory overtime and six-day weeks.

United has previously criticized FAA delays at its New

Jersey hub even on good weather days. In November it was forced

to reduce traffic there because of low FAA staffing on a dozen

days disrupting more than 343,000 United travelers.

Newark has suffered flight disruptions for years and CEO

Scott Kirby has sharply criticized the FAA performance.