TEHRAN, Iran — Iranian reformists appear have won all 30 seats representing the nation’s capital in parliament, a definitive rebuke to the hard-liners opposing President Hassan Rouhani’s efforts to open the economy and cooperate with the West.

In the first elections held since last year’s nuclear deal, none of Iran’s three main political camps — reformists, conservatives and hard-liners — is expected to win an outright majority in the 290-seat parliament, but early results indicate the best reformist showing in more than a decade. MORE