Metro board member Corbett A. Price says the agency should consider canceling the Silver Line extension to save money. (Astrid Riecken/For The Washington Post)

In an apparent effort to pressure Virginia and its suburbs to contribute more money to Metro, a board member said Tuesday that he will ask the agency to consider canceling the $5.8 billion Silver Line extension, which is expected to open in 2020.

The proposal from board member Corbett A. Price, who represents the District, was immediately dismissed by Virginia officials, who said cancellation would break contracts and trigger lawsuits without necessarily saving any money. The second phase of the 23.1-mile line is well underway.

Sharon Bulova (D), chair of the Fairfax County Board of Supervisors, called the suggestion “pretty ridiculous.” Virginia Transportation Secretary Aubrey Layne said it was “more rhetoric than somebody actually running the numbers.”

The dispute was the latest sign of tension between the District and the Washington suburbs over how to run Metro. The city also has been at odds with Maryland and Virginia over late-night service cuts.

Price, a businessman who represents Mayor Muriel E. Bowser (D) on the Metro board, said the agency can’t afford the extra costs of operating the Silver Line if it is extended as planned.

If Northern Virginia wants to finish the project, Price said, it should be willing to pay for its operations by approving a tax or other dedicated funding source for Metro. He said he will propose that Metro discuss the proposal as early as Thursday’s board meeting.

“Based on my analysis, we ought to look at forgoing the Silver Line,” Price said. “How can you continue to expand when you’re currently in a deficit situation and the expansion project is going to put you further into deficit?”

Metro is not paying for construction of the line in Northern Virginia — it is being financed through a combination of federal, state and local funds raised in part through special taxing districts.

Dulles Toll Road users are paying for more than 70 percent of the project’s cost.

Construction of the Silver Line is being managed by the Metropolitan Washington Airports Authority. Once completed, each phase is handed over to Metro, which assumes responsibility for maintenance and operations. The first phase of the project — five stations in Reston and Tysons — opened in July 2014. The second phase has six stations, including one at Dulles Airport, and for the first time extends Metro service into Loudoun County. Construction has begun on five of the six stations, and the project is nearly 47 percent complete.

Price said canceling the extension would save about $100 million over two fiscal years beginning in mid-2018, at a time when the District and other jurisdictions are concerned about rising financial demands from Metro for increased government subsidies.

Metro Board Chairman Jack Evans (D), who also represents the District, said he supports Price’s idea.

“Mr. Price’s observation that we may have to just stop moving forward with the Silver Line may make sense in light of the enormous financial challenges that we face,” said Evans, who also is a D.C. Council member. “It just goes back to the need for a dedicated funding source.”

Metro is struggling to close a $290 million budget deficit for the fiscal year beginning July 1. It could involve a mix of fare increases, service cuts and increased subsidies from the District, Maryland and Virginia.

In addition, Metro has put the jurisdictions on notice that it will be asking for higher-than-expected subsidies in coming years. The District has said its share of the unexpected new burden — for operating expenses and capital investments — will exceed $650 million over the next three fiscal years.

The District has been calling for the region to approve a regionwide sales tax or other reliable revenue source to fund Metro’s growing needs for both operational subsidies and capital funds to pay for maintenance, new equipment and other investments.

Evans said Virginia and Maryland ought to speed up plans to seek such a tax. In their 2017 legislative sessions starting in January, he said, the states should propose to allow the suburban jurisdictions served by Metro to tax themselves to support the transit system.

Local officials and business leaders, instead, have been planning to wait until early 2018 to make such proposals in Richmond and Annapolis, giving them time to develop a common regional proposal and lobby for it.

Bulova reaffirmed Virginia’s position that it would not consider dedicated funding until Metro has made progress on current problems.

“It is way too premature to suggest a new funding stream without being sure that management issues, safety issues and governance issues are being addressed,” Bulova said.

Virginia residents already pay a portion of their sales tax for transportation. In addition, Republican legislators in the GOP-led General Assembly have promised to block any tax increases for Metro.

Metro is the only major U.S. transit system that does not receive a significant amount of its funds from a dedicated source. This has been identified repeatedly as a major shortcoming that contributes to underinvestment in the system.

Maryland has said it is unwilling to consider additional funding unless Metro is willing to create benchmarks to measure its improvement.

Layne said it would be costly to break contract obligations to cancel the Silver Line extension. He noted that debt has already been issued for the project.

“It may be more expensive to stop than it is to go forward,” Layne said. “I would suggest a thorough review of that before any decision were made.”

Bulova suggested that Price and Evans were not serious about killing the project but were instead trying to put pressure on Virginia officials.

“Frankly, I think essentially that suggestion is merely provocative and not a real recommendation,” Bulova said. “They’re poking us.”

She said landowners along the Silver Line route, who were paying higher taxes to support the project, would object if it were canceled.

Price was dismissive of that concern, saying, “That’s Virginia’s responsibility. That’s not Metro’s.”

Lori Aratani contributed to this report.