WASHINGTON, Aug. 10 (Xinhua) -- U.S. Vice President Mike Pence said Thursday that the United States plans to establish a Space Force by 2020, an idea pushed by President Donald Trump but questioned by many top brass at the Pentagon.

"The time has come to establish the United States space force," Pence told a gathering at the Pentagon, citing Trump's directive earlier this year to form the sixth branch of armed forces.

"It is not enough to merely have an American presence in space. We must have American dominance in space and so we will," Pence said in his speech.

In agreement with Pence's speech, the Pentagon laid out its plans to formulate the new branch of military in a 15-page report, identifying immediate steps of action, including establishing a Space Development Agency, "a joint organization charged with rapidly developing and fielding next-generation capabilities."

The report also called for the creation of a Space Operations Force, which it said will be made up of career space experts who are "trained, promoted and retained as space war fighting professionals."

Also in the pipeline is a United Combatant Command-level Space Command, which will be tasked to "improve and evolve space war fighting."

Although not clearly outlined in the report, Pence announced that the Pentagon will create a new Assistant Secretary of Defense of Space, the top civilian position to oversee the creation of the new branch who will report to Pentagon Chief Jim Mattis.

Pence said funding for the new military branch will be requested in the fiscal year 2020 defense budget, and called on Congress to approve an "additional 8 billion dollars in space security systems."

U.S. media first reported on the plan in late July. The Pentagon had later on decided to postpone the release of the report. The final version was very similar to the content that was leaked in July.

Though the Trump administration has made ambitious pledges to bolster its ability to militarize space, the broad strokes of the plan fail to answer questions such as what a U.S. comprehensive space strategy looks like and whether an independent military branch is the necessary means to achieve it.

Stefan Soesanto, an expert with the think tank Pacific Forum, said legal and strategic questions need to be addressed before moving forward with the Space Force initiative.

"The first question that we need to clarify is whether the U.S. and its future peer adversaries are willing to fight a war in space," Soesanto said in a commentary questioning the necessity of a Space Force.

While no wars have yet been conducted beyond the atmosphere, and with continuing efforts by other countries to keep space free of military conflict, it's unclear what military fighting, if any, would look like among the satellites.

Even if war breaks out in outer space, Washington should determine a number of legal elements, such as should an attack on U.S. assets in space constitute an attack on U.S. soil? How should the United States regard private, foreign, or international space assets in times of war? Short of a commonly accepted norm, war fighting in space can easily escalate into an all out nuclear war, Soesanto argued.

The concerns, as well as cost calculations, have hampered the enthusiasm among lawmakers and top brass for the new military branch, with many suggesting elevating the Space Command from under the U.S. Air Force to a Unified Combatant Command as a more prudent move.

Jim Inhofe, a Republican senator and the number two on the Senate Armed Services Committee, has openly rebuked the suggestion of creating a new branch of military. "I know the president has strong feelings. I think we can do that without a new branch," he told the media early this month.

Air Force Secretary Heather Wilson said a new branch of military will create a layer of bureaucracy that hinders, not boosts war fighting capabilities.

"This will make it more complex, add more boxes to the organization chart, and cost more money. If I had more money, I would put it into lethality, not bureaucracy," she said.

Pence noted in his speech that "creating a new branch of the military is not a simple process." It is yet unclear to what lengths the Trump administration is willing to go against the advice of lawmakers and his top generals.