Cryptocurrency prices jumped after President Donald Trump’s surprise announcement he wants the U.S. government to purchase and hold a variety of digital assets in a strategic reserve fund, an announcement that highlights Trump’s growing attempts to use volatile cryptocurrency prices as a barometer of his public support.

President Donald Trump said Sunday that he is directing his newly created digital assets working group to move forward on creating a “crypto strategic reserve” along the lines of existing U.S. reserves of gold and oil.

The first five currencies that will be included in a U.S. strategic crypto reserve are Bitcoin, Ethereum, Ripple, Solana, and Cardano.