Air traffic control staffing issues are causing delays at major eastern US airports and a halt on some departing flights, according to the Federal Aviation Administration.

The exact scope of the problem remains unclear, but the delays are impacting at least New York's airports and Philadelphia airport.

LaGuardia is currently operating under a ground delay, with some arriving flights experiencing an average delay of 1h 26min, says the FAA's flight delay information webpage. Delta Air Lines, which is the biggest carrier at the airport, says it is experiencing delays to about 200 flights at LaGuardia and other airports in the northeast.

The FAA had also reported delays of more than two hours at other affected airports, which include Newark Liberty International airport and Philadelphia.

"We have experienced a slight increase in sick leave at two facilities," says the FAA in a statement posted on Twitter. "We are mitigating the impact by augmenting staffing, rerouting traffic and increasing spacing between aircraft."

The FAA's website attributes the issues to "ZDC + ZJX staffing". ZDC is the code of the FAA's control site in the Washington, DC area, while ZJX is a site near Jacksonville, Florida.

Among the other major US carriers, Southwest Airlines says it is experiencing some flight delays, but have not cancelled any flights yet. United Airlines says it does not anticipate "significant schedule disruptions" at the moment. "We’re working closely with FAA and airport officials to try to minimise the impact on our operations and, most importantly, on our customers," says the Chicago-based carrier.

American Airlines did not immediately comment on the impact to their operations.

The delays come during a partial shutdown of the US government that has left air traffic controllers working without pay. Unions representing controllers have urged lawmakers to end the shutdown, and in recent days media have reported that some controllers have resigned due to lack of pay.

Story updated with United and Delta comment

Source: Cirium Dashboard