Crypto critic Sen. Elizabeth Warren cautioned House lawmakers working on a bill to regulate stablecoins that the assets pose risks to the banking system and national security, according to a letter obtained by Politico.

In a letter to House Financial Services Committee Chair Patrick McHenry, R-N.C., and Rep. Maxine Waters, D-Calif., Warren was critical of their efforts to push forward a stablecoin bill, which has already faced its own hurdles over the past year. 

"Efforts to create new regulatory frameworks around the $157 billion stablecoin market, including those that aim to fold stablecoins deeper into the banking sector, could amplify and entrench these risks rather than mitigate them," Warren said in the letter dated April 8. "I urge you to remember the gravity of these risks …