U.S. Customs and Border Protection has denied a proposal to fly tourists between Fairbanks, Alaska, and Dawson City, Yukon, saying the agency cannot provide the staff that would be required.

Holland America Line wanted to begin the flights next summer, using Yukon's Air North to shuttle as many as 19,000 people between the two destinations. The tour company envisioned nine weekly flights as a way to cut down the time visitors would spend on its buses, allowing an expanded schedule in Fairbanks or Dawson City.

Customs officials, however, said the agency doesn't have the staff available to accommodate the plan. In a letter to Air North, CBP's Anchorage-area port director Lance E. Robinson said it would be "an inefficient use of our existing resources" to relocate workers to Fairbanks to support the flights.

"Ultimately, the impact on CBP's existing operations proves too significant to support the request as outlined," he stated.

The action has prompted a response from U.S. Sen. Lisa Murkowski. The office of the Alaska Republican said she plans to formally support an appeal filed by Air North. Murkowski's staff has met with customs officials to discuss the matter as well.

In a letter to acting Commissioner Thomas Winkowski, the senator said she had "grave concern" with the staffing levels at Fairbanks International Airport that led to the denial of the additional flights.

Holland America spokesman Erik Elvejord said the company is hoping for a resolution that could allow the flights to proceed next year.

"An appeal is under way to revisit the situation and review this request further," Elvejord said in an email. "We are hopeful this review will result in a greater understanding of the economic benefits to the region and lead to a positive outcome for all concerned."