A runway that’s been under construction for a few months at Newark Liberty International Airport reopened on Monday, 13 days ahead of schedule.

The rehabilitation came at a time when the airport was facing a number of issues, including an air traffic controller shortage and communication outages.

The Federal Aviation Administration reduced the number of flights in and out of Newark in response to the issues. It’s currently capped at 56 total departures and arrivals. However, it is expected to be increased to 68 per hour by mid-June.

Flights have already begun taking off from the new runway, but it is still being cleared for arrivals. According to Transportation Secretary Sean Duffy, this should happen by the end of June or early July.

“We had three problems,” said Duffy. “One - the runway was being rebuilt. We had a telecom issue. New fiber is laid, but it has to be tested. And then we have the staffing issue with the air traffic controllers."

RELATED: New fiber line laid between Philly and New York to improve air traffic control system, Duffy says

According to Duffy, the new cable should be up and running by the end of the month or early July at the latest. It will improve communication between Newark and Philadelphia, where air controllers handle Newark Liberty arrivals and departures.

“The problem we’re seeing with controllers can’t be fixed overnight. It takes time to train up on this airspace,” said Duffy.

The secretary also said that 22 air traffic controllers are being trained in Philadelphia and are expected to be ready to work on a rolling basis over the course of a year at most. Sixteen are familiar with the Newark airspace, Duffy said.

“All of those things on a rolling basis are going to come online and as that happens, we’re going to be able to expand the capacity of the airport,” said Duffy. “But you can’t snap your fingers and make it happen.”

The number of flights in and out of the airport is capped through the fall.