Presidential candidate Donald Trump’s plan to deport all undocumented immigrants would cost between $400 billion and $600 billion and take at least 20 years to implement, according to a report from the American Action Forum.

The report estimates that there are currently 11.3 million undocumented immigrants currently living in the United States. To deport them, these individuals would have to be apprehended, detained, legally processed, and transported back to the country they originated from.

In order to do this in two years like Trump has proposed, the report estimates that there would need to be 90,582 federal immigration apprehension employees, 348,831 immigration detention beds, 1,316 immigration courts, 32,445 federal attorneys to process undocumented immigrants, and a minimum of 17,296 chartered flights and 30,701 chartered bus trips.

"If the federal government were to remove all undocumented immigrants in only two years, it would require a massive expansion of the federal government’s immigration enforcement personnel and infrastructure," states the report.

The report says that if the federal government began enforcing mass deportation, about 20 percent of undocumented immigrants would begin to leave voluntarily which would leave about 9 million illegal aliens in the country. Currently, U.S. Immigration and Customs Enforcement only has the capacity to remove 400,000 undocumented immigrants in one year.

"That means if ICE were to operate at its current maximum capacity, it would take over 20 years to remove 9.04 million undocumented immigrants," states the report. "To remove those 9.04 million immigrants in two years, ICE would have to remove 4.52 million immigrants per year. That is 11.3 times larger than ICE’s current maximum capacity."

"This is an enormous budgetary stress at a time when we really have big problems already," said Douglas Holtz-Eakin, president of the American Action Forum "It’s an enormous expansion of the federal government at a time when a lot of people are saying wait, the government has gotten too big already."

The Trump campaign did not respond to requests for comment by press time.