U.S. Secretary of State Antony Blinken said on Monday that the United States is still confused whether Iran is ready to resume compliance with its 2015 nuclear deal and if Tehran continues to violate the pact, the “breakout time” it needs to amass enough fissile material for a single nuclear weapon will shrink to weeks.

“It remains unclear whether Iran is willing and prepared to do what it needs to do come back into compliance,” Blinken told lawmakers.

“Meanwhile, its program is galloping forward. … The longer this goes on, the more the breakout time gets down … it’s now down, by public reports, to a few months at best. And if this continues, it will get down to a matter of weeks.”