The White House on Monday called GOP efforts to defund Obamacare and win more spending cuts at the risk of a government shutdown or default “utterly irresponsible” and warned the president would not negotiate with Republicans.

“Congress needs to act responsibly to ensure that the government does not shut down,” White House spokesman Jay Carney told reporters. “[President Obama] has made it abundantly clear that fiddling around with the prospect of default is utterly irresponsible and we cannot do it.”