WASHINGTON (AP) — Secretary of State John Kerry says time is running out for Iran to negotiate a comprehensive agreement on its nuclear program.

In a Washington Post opinion piece late Monday, Kerry says the July 20 deadline is fast approaching and that Tehran’s leaders face a choice: “They can agree to the steps necessary to assure the world that their country’s nuclear program will be exclusively peaceful … or they can squander a historic opportunity to end Iran economic and diplomatic isolation and improve the lives of their people.”