(CNN) -- There is growing concern within the US military about the costs of President Donald Trump's proposed military parade and the disruption it could cause.
If Trump insists on a military parade through Washington involving thousands of troops, armored vehicles, missiles and other heavy weapons the event could disrupt crucial military training schedules, according to a defense official directly familiar with the initial planning efforts.
There are also concerns over the cost of the event, and a second defense official tells CNN that the Pentagon is considering seeking out private donations to offset some of the non-military costs of the event. The donations could not cover military salaries or the cost of moving equipment but they could be used to pay for other aspects of the parade.
There are no firm cost estimates until President Trump orders the military to stage a specific event, but very preliminary estimates suggest the cost could run between $3 million and $50 million, the first official said, emphasizing that nothing is certain at this point. There is no money currently allocated for a parade in the defense budget. Budget director Mick Mulvaney said Wednesday that he has seen estimates that a military parade could cost $10 million to $30 million.
On wider concerns about a large scale parade, "we don't have troops and units sitting around waiting to do a parade," the first defense official said. A large parade could require weeks of preparation, including the early shipment of equipment such as tanks, and personnel would need to arrive days ahead to be ready to man the gear during a parade.
One solution being considered to alleviate that concern is a so-called multimedia option, which could include a concert and large video screens on the National Mall displaying images of military gear rather than bringing large amounts of hardware to Washington, the official said.
The Army, which is in charge of developing options for a parade or celebratory event, has compiled five preliminary options that have been forwarded to Pentagon leadership.
The initial options are broadly characterized as "small, medium, heavy, hybrid and a multimedia display." Each could be fine-tuned to meet specific requests by Trump.
The small and medium options could include varying levels of troops marching from ceremonial units stationed in Washington and some equipment located nearby from the Maryland and Virginia National Guard.
The so-called heavy option would bring active duty units to Washington. Generally, all active duty units that are not deployed have ongoing and regular stateside training and exercise commitments that may have to be halted if they were involved in a parade.
According to the official, one indicator of the Pentagon's lack of enthusiasm for the project is that the Defense Department told the Army to include a significant amount of aircraft in the ceremony to mitigate the burden on ground forces.
The Pentagon is not commenting on potential options. Chief spokesperson Dana White told CNN her previous public comments still stand. On February 8 she told reporters, "We're still in the nascent stages. When we have those options, we will provide that to the White House, and the President will decide. "
Defense Secretary James Mattis and Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, have publicly said the department will develop options to address the President's request for a parade. Trump brought up the matter after seeing France's Bastille Day celebrations in Paris last year but did not specify what he wanted.
Pentagon officials have previously indicated they may look to schedule an event on November 11, which is Veterans Day. This year is the 100th anniversary of the end of World War I.
Several commemorations are already planned in Europe with US forces participating. One advantage of holding the event Trump wants in November is that with cooler weather, there is less potential for damage to city streets from heavy equipment being driven on them.
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