Iran is on the pathway to fully restarting its contested nuclear weapons program due to insufficient international inspections of its military sites and caveats in the landmark nuclear deal that permit it to reengage in nuclear enrichment work within the next several years, according to experts who testified Wednesday before Congress.

Ahead of President Donald Trump’s expected announcement to decertify Iranian compliance with the nuclear deal, top lawmakers on the House Foreign Affairs Committee urged the administration to preserve the agreement and focus on more aggressive enforcement.

Reps. Ed Royce (R. Calif.) and Eliot Engel (D., N.Y.), the chair and ranking member of the committee, both advised the Trump administration to “enforce the hell out of” the deal, rather than abandon it.

They offered this advice despite testimony by leading nuclear experts that Iran has repeatedly violated agreement and could be back on the pathway to a nuclear weapon within the next five or six years.