WASHINGTON (AP) — Former Secretary of State Hillary Rodham Clinton is warning Congress that new unilateral sanctions against Iran could upend sensitive international negotiations over its nuclear development, imploring lawmakers to work with the Obama administration in presenting a unified front to Tehran.

Echoing President Barack Obama’s deep concerns about another round of tough economic penalties, Clinton said any congressional action could undercut U.S. work with its allies as well as American influence with Russia and China in forcing Tehran to negotiate after years of inconclusive talks.