Airlines across the world, including the long-haul carrier Emirates, rushed Wednesday to cancel or change flights heading into the U.S. over an ongoing dispute about the rollout of 5G mobile phone technology near American airports.

The issue appeared to particularly impact the Boeing 777, a long-range, wide-body aircraft used by carriers worldwide — especially Emirates. Two Japanese airlines directly named the aircraft as being particularly affected by the 5G signals as they announced cancellations and changes to their schedules.

The cancellations come even after mobile phone carriers AT&T and Verizon said they will postpone new wireless service near some U.S. airports planned for this week. The FAA has cleared a number of aircraft to fly into airports with the 5G signals, but missing from the list is the Boeing 777.

Dubai-based Emirates, a key carrier for East-West travel, announced it would halt flights to Boston, Chicago, Dallas-Fort Worth, Houston, Miami, Newark, New Jersey, Orlando, Florida, San Francisco and Seattle over the issue beginning Wednesday. It said it would continue flights to Los Angeles, New York and Washington.

In its announcement, Emirates cited the cancellation as necessary due to “operational concerns associated with the planned deployment of 5G mobile network services in the U.S. at certain airports.”

“We are working closely with aircraft manufacturers and the relevant authorities to alleviate operational concerns, and we hope to resume our U.S. services as soon as possible,” the state-owned airline said.

The United Arab Emirates successfully rolled out 5G coverage all around its airports without incident, like dozens of other countries. But in the U.S., the Federal Aviation Administration worries that the C-Band strand of 5G could interfere with radio altimeters.

Altimeters measure how high a plane is in the sky, a crucial piece of equipment for flying, particularly at night or in bad weather.

The FAA will allow planes with accurate, reliable altimeters to operate around high-power 5G. But planes with older altimeters will not be allowed to make landings under low-visibility conditions.

Part of the problem, according to the FAA, are the signal strength of the 5G towers.

“Base stations in rural areas of the United States are permitted to emit at higher levels in comparison to other countries which may affect radio altimeter equipment accuracy and reliability,” the FAA said in December.

The U.S. Federal Communication Commission's chairwoman said in a statement that the 5G “deployment can safely co-exist with aviation technologies in the United States, just as it does in other countries around the world.” However, Jessica Rosenworcel added: "It is essential that the FAA now complete this process with both care and speed.”

AT&T and Verizon spent tens of billions of dollars for C-Band spectrum in a FCC government auction last year.

Of particular concern in the 5G rollout appears to be the Boeing 777, a major workhorse for Emirates, which only flies that model and the Airbus A380 jumbo jet. Its Mideast competitor, Qatar Airways, anticipates “minor delays” on return flights from the U.S. but says otherwise its dozen U.S. routes are operating as scheduled.

Japan's All Nippon Airways Co. Ltd. said in a statement that the FAA “has indicated that radio waves from the 5G wireless service may interfere with aircraft altimeters.”

“Boeing has announced flight restrictions on all airlines operating the Boeing 777 aircraft, and we have cancelled or changed the aircraft for some flights to/from the U.S. based on the announcement by Boeing,” ANA said. It cancelled 20 flights to the U.S. over the issue to cities such as Chicago, Los Angeles and New York.

Japan Airlines Co. Ltd. similarly said that it had been informed that 5G signals “may interfere with the radio altimeter installed on the Boeing 777.”

“We will refrain from using this model on the continental United States line until we can confirm its safety and we regret to inform you that we will cancel the flight for which the aircraft cannot be changed to the Boeing 787,” the airline said. Eight of its flights were affected Wednesday — three passenger trips and five for cargo.

Chicago-based Boeing Co. did not immediately respond to a request for comment.

Air India also announced on Twitter it would cancel flights to Chicago, Newark, New York and San Francisco “due to deployment of the 5G communications” equipment. It said it would try to use other aircraft on U.S. routes as well.

Korean Air, South Korea’s biggest airline, switched four passenger planes from Boeing 777s to 787s and two cargo planes from 747-8s to 747-400s overnight, and will continue to avoid operating 777s and 747-8s at affected U.S. airports, spokeswoman Jill Chung said.

Hong Kong’s Cathay Pacific said it is deploying different types of airplanes where necessary to the affected airports and that its flights to the United States have not been affected so far. Taiwan's EVA Air also said it had taken “contingency measures to ensure flight safety,” without elaborating.

German airline Lufthansa said it had substituted Boeing 747-400 aircraft instead of 747-800s on three flights from Frankfurt to Los Angeles, Chicago and San Francisco, while cancelling one connection from Frankfurt to Miami. Austrian Airlines swapped a Boeing 767 in place of a 777 for one flight from Vienna to Newark.

Choi Jong-yun, a spokeswoman of Asiana Airlines, another South Korean carrier, said the company hasn’t been affected so far because it uses Airbus planes for passenger flights to the U.S. and doesn’t use the affected Boeing planes to transport cargo.

However, Choi said airlines have also been instructed by the FAA to avoid automatic landings at affected U.S. airports during bad weather conditions, regardless of plane type. Asiana will redirect its planes to nearby airports during those conditions, she said.