beirut iranian president hassan rouhani defend nuclear deal western power saturday say u.s. president donald trump could undermine 2015 deal iran agree limit dispute nuclear program return ease economic sanction however trump expect announce soon decertify deal senior administration official say step potentially could cause accord unravel nuclear negotiations agreement reach issue benefit reversible one turn back mr. trump anyone else rouhani say ceremony tehran university mark start university academic year accord state media even 10 trump create world reversible trump call pact embarrassment bad deal ever negotiate weigh whether deal serve u.s. security interest face oct. 15 deadline certify iran comply term prospect washington renege deal worry u.s. ally help negotiate especially world grapple another nuclear crisis north korea nuclear ballistic missile development trump certify iran compliance u.s. congress 60 days decide whether reimpose sanction waive deal u.n. inspectors verify iranian compliance term rouhani say saturday unite state violate deal would hurt reputation international community america carry violations today whole world condemn america condemn iran rouhani say accord state media say trust america sign agreement separately former iranian president mohammad khatami forbid attend public political cultural promotional ceremonies period three months two lawyers tell iranian labour news agency ilna saturday khatami long lightning rod criticism hardliners accuse foment unrest protest follow dispute election president mahmoud ahmadinejad 2009. local media forbid quote khatami article publish image new restrictions issue iranian security force khatami lawyers tell ilna appear judicial mechanism dispute restrictions lead-up presidential election last may khatami post message online encourage supporters vote rouhani rouhani make reference new restrictions place khatami speech saturday name anybody repeat people come ballot box punish say accord ilna khatami lawyers tell ilna restrictions begin first day iranian month mehr sept. 23. iranian president defend nuclear deal say trump undermine