LOST REFEREENDUM: Italian Prime Minister Matteo Renzi and his wife at the voting.

Italian Premier Matteo Renzi announced he will resign today after suffering a stinging loss in a reforms referendum, triggering immediate calls from a populist party and other opposition forces for elections to be held soon.

‘‘The ‘No’s’ have won in an extraordinary clear-cut way,’’ Renzi told reporters in Rome about an hour after polls had closed in Sunday’s balloting.

‘‘I lost and the post that gets eliminated is mine,’’ Renzi said. ‘‘The government’s experience is over, and in the afternoon I’ll go to the Quirinal Hill to hand in my resignation’’ to President Sergio Mattarella.

Leaders of the populist 5-Star Movement, which is led by comic Beppe Grillo, joined the chorus for early elections. The 5-Stars are the chief rivals of Renzi’s Democrats and are anxious to achieve national power for the first time.