The second explosion occured in the mausoleum of Imam Khomeini in the Iranian capital, IRIB TV channel reported.
"Another terrorist just blew himself up on the terroritory of the Imam Khomeini shrine," the news outlet reported via its Telegram channel.
"Based on primary reports, 1 killed, 5 injured in shooting spree at Imam Khomeini shrine," the Mehr news service posted on its Twitter account.
Multiple Iranian outlets including Mehr reported earlier that a third assailant had reportedly detonated his suicide vest. The latter cited reports of two assailants being arrested at the site.