"Demonstrators wanted to attack the prefecture but police prevented them. Then they attacked the town hall, and police opened fire and used tear gas," the deputy governor of Khuzestan province told the student news agency ISNA on Sunday
The incident took place in Izeh district on Saturday, ISNA said.
"The deputy elected, Seyed Hadi Tabatabai, is safe and sound," added the official, whose name was not given. He explained the protesters were contesting the results that saw the conservative candidate win.
Also on Sunday, the interior ministry announced the turnout in the elections was 50.57% of the country's 46.3 million eligible voters.
The nationwide participation in the polls is the lowest for major elections in the 25-year history of the Islamic republic, and a sharp drop from the last Majlis poll in 2000, when 67.35% of the electorate turned out.
Turnout on Friday in Tehran province, which includes the capital and surrounding towns and villages, was 33.77%.
In the capital itself, turnout was 28% of the electorate.
The interior ministry said during Friday's polling, 23,438,030
out of 46,351,032 eligible voters cast their ballots.
Only municipal elections last year and 1998 polls for the
Assembly of Experts - the body that appoints the country's supreme leader - saw a lower turnout at 49.17% and 46.32% respectively.
Turnout became a major issue in the polls, after some incumbent reformists and pro-democracy activists called for a boycott after more than 2300 people - most of them reformers - were barred from even standing for parliament.
The regime, however, launched an all-out campaign for a high