WASHINGTON — Federal officials temporarily restricted flights Friday into and out of New York's LaGuardia Airport, another example of the toll that the partial government shutdown — in its 35th day — is taking on the nation's airports. 

"We have experienced a slight increase in sick leave at two facilities," a spokesman for the Federal Aviation Administration said in a statement. "We've mitigated the impact by augmenting staffing, rerouting traffic and increasing spacing between aircraft when needed. The results have been minimal impacts to efficiency while maintaining consistent levels of safety in the national airspace system."

White House press secretary Sarah Sanders said Friday that President Donald Trump had been briefed on the situation.

"We are in regular contact with officials at the Department of Transportation and the FAA," she said.

The delays came a day after elected officials and union leaders warned about dangers posed to the nation's air traffic system because of the prolonged government shutdown. The restrictions at La Guardia were causing ripple effects at other airports, with delays reported at Newark's Liberty International Airport and Philadelphia International Airport.

Friday's announcement by the FAA is significant because it is the first time there has been a shortage of air traffic controllers. The Transportation Security Administration has struggled to keep security checkpoints operating at airports, but while those shortages may increase airport wait times, they do not affect how planes are managed once they are in the air.

"This is exactly what [Association of Flight Attendants] and other aviation unions have been warning would happen. The aviation system depends on the safety professionals who make it run," said Sara Nelson, the group's president. "They have been doing unbelievably heroic work even as they are betrayed by the government that employs them. They are fatigued, worried and distracted, but they won't risk our safety. So the planes will stay on the ground. This is anything but a sickout — it is only about our safety and the air traffic controllers' absolute commitment to it."

Many federal workers, including TSA officers and air traffic controllers, have been working without pay since the shutdown began. They normally would have been paid Friday.

Travelers were advised to check with their airline for more information.

The FAA's Airport Status Information website cited shortages at two facilities, including one near Washington that manages air traffic. The temporary restrictions affect arriving and departing flights at the airport. Arriving flights were delayed an average of 41 minutes, and departures were experiencing delays of between 15 and 29 minutes, the FAA said.