President Donald Trump wants US allies to pay all costs associated with hosting US troops and a bit more, Bloomberg News reported Friday.

Under the audacious plan, allies would pay all costs plus 50% more for the privilege of hosting US troops in their countries.

The Trump administration plans to demand that US allies pay the full cost for hosting American troops, plus 50% more for the privilege of hosting them, Bloomberg News reported Friday, citing a dozen administration officials and people it said had been briefed on the situation.

The plan targets allies such as Germany and Japan but is expected to extend to any country that hosts US military personnel. With the "Cost Plus 50" plan, some countries could wind up paying as much as six times what they pay now to host US troops.

Last month, South Korea agreed to pay just shy of $1 billion, significantly more than the previous $800 million, to host US troops. Bloomberg reports that President Donald Trump demanded "cost plus 50" in recent payment negotiations with South Korea and that it nearly derailed talks.

Trump has long railed against allies for not paying what he considers their fair share for US defense.

"We defend Japan. We defend Germany. We defend South Korea. We defend countries. They do not pay us what they should be paying us," he said during the first presidential debate in September 2016. "We are providing a tremendous service, and we're losing a fortune."

"Wealthy, wealthy countries that we're protecting are all under notice," the president said at the Pentagon in January. "We cannot be fools for others."

Since he took office, he has repeatedly pressed NATO countries to spend at least 2% of their gross domestic product on defense as some countries pledged to do by 2024.

The Cost Plus 50 plan, according to Bloomberg, has alarmed both the State Department and the Defense Department, with rising concern that such a move could weaken the alliances at a time when the US is again facing great-power competition from rivals like China and Russia.

Countries such as Japan and Germany are already becoming increasingly resistant to the presence of the US military within their borders, and there are concerns that demands for larger payments could make the host countries even more hostile to the idea of hosting US troops.

"Getting allies to increase their investment in our collective defense and ensure fairer burden-sharing has been a long-standing US goal," the National Security Council spokesman Garrett Marquis told Bloomberg. "The administration is committed to getting the best deal for the American people," he added, while refusing to comment on ongoing deliberations.

It remains to be seen whether the Trump administration will announce the Cost Plus 50 plan as is or lessen the steep new demands.