Kurdish Iranian dissident groups based in northern Iraq are preparing for a potential cross-border military operation in Iran, and the U.S. has asked Iraqi Kurds to support them, Kurdish officials have told The Associated Press.

Iran is striking a hard line after just one day of restarted talks in Vienna over its tattered nuclear deal.

The White House is responding skeptically after Iran’s chief negotiator announced that Tehran is ready to return to nuclear negotiations in Vienna by the end of next month.