Sept. 26 (UPI) -- Puerto Rico's main airport has effectively been crippled by Hurricane Maria, leaving travelers stranded as they try to get off the island.
Because of a lack of electrical power, planes at Luis Marin Munoz International Airport are limited to takeoffs during the daylight -- meaning most passengers can't depart the island.
Planes carrying disaster relief are arriving at the airport.
All reservations were being confirmed through a phone line to Miami, and hundreds of departing passengers were waiting at the airport in stifling heat. Computers used to manage boarding passes and luggage were out of order five days after the hurricane stuck the island.
The Federal Aviation Administration said most of the airport's radar and navigation equipment, damaged by the storm, is now operational. It added that one long-range radar site atop a mountain will be unusable until workers with chainsaws can cut their way through 2 miles of debris and downed trees.
It's unclear how long it might take before the airport can resume normal operations. Officials have previously said it may take a month to restore power to Puerto Rico.
In the meantime, the power outages are affecting some of the commonwealth's most vulnerable, San Juan Mayor Carmen Yulin Cruz told CNN.
"We are finding dialysis patients that haven't been able to contact their providers, so we are having to transport them in near-death conditions," Yulin Cruz said, recalling a group's visit to two San Juan-area nursing homes this week. "We are finding people whose oxygen tanks are running out, because ... small generators now don't have any diesel."
"This has been a devastating hurricane. This is a humanitarian crisis. The images and the stories coming out of the island have been heart breaking and devastating. This is our country and these are our citizens. They need help and they are going to get our help. I want the people of Puerto Rico to know that we are in this with them," Ryan said.
Ryan added that Congress will act when President Donald Trump sends it an aid request.
The speaker's promises come as Democratic leaders are critical of Trump for what they see as an inadequate response to the devastation in Puerto Rico. Among them is former presidential candidate Hillary Clinton, who suggested Tuesday that the U.S. Navy get involved in relief efforts.
The U.S. Coast Guard has nine ships in the vicinity of Puerto Rico.
"We still need some more help. This is clearly a critical disaster in Puerto Rico," Gov. Ricardo Rosselló said.
Trump announced Tuesday that he will visit Puerto Rico and possibly the U.S. Virgin Islands next Tuesday.
"We have shipped massive amounts of food and water and supplies to Puerto Rico, and we are continuing to do it on an hourly basis, but that island was hit as hard as you could hit," Trump said.
A satellite view of Puerto Rico dramatically showed that few areas of the island have electrical power.