The United States Tuesday called for restraint by Iranian authorities in dealing with unrest by minority Arabs in Iran's Khuzistan province, bordering Iraq.  At least five people have been reported killed in clashes there that began late last week.

The ethnic Arabs of Khuzistan, an oil-rich area along the Iraqi border, have long complained of discrimination by central authorities in Tehran including curbs on their rights to study and speak Arabic.

News reports say as many as five people have been killed and more than 200 arrested in clashes between protesters and security forces that began last Friday, sparked by rumors that Iranian authorities planned to change the ethnic mix in the region.

At a news briefing, State Department Deputy Spokesman Adam Ereli said the United States is "very concerned" by the reports.

The spokesman called on Iranian authorities to exercise restraint in dealing with the protests and to respect the peaceful exercise by Iranian citizens of democratic rights, including the right to freely assemble and demonstrate.

"In our view, this unrest and these arrests involve the denial of rights of minority groups in Iran,? said Mr. Ereli. ?The group is an Arab group, it's my understanding. And the suppression of minority rights is obviously to be denounced, and it is not the first time that Iran has practiced this kind of human rights violation, and it's reflected in our human rights report on Iran."

In its latest global report on human rights, issued in late February, the State Department said Iran's already-poor human rights record worsened over the preceding year.

It quoted foreign representatives of the ethnic Awazi Arabs of Khuzistan as saying Iranian authorities shut down two bilingual Arabic-Farsi newspapers in the area last year and imprisoned scores of political activists, some allegedly tortured for criticizing government policies.

The U.S. report said the group also complained that the Tehran government has ignored appeals to de-mine vast stretches of Khuzistan sown with mines during the Iran-Iraq war in the 1980's.

News accounts of the latest unrest said ethnic Arabs in the provincial capital city of Ahvaz attacked and set fire to police stations and banks, and that security forces responded with tear gas and rubber bullets.

The unrest was sparked by circulation of a letter allegedly written by a former government official describing a plan to move non-Arabs into Ahvaz to make them the majority in the city.

The purported author of the letter says it is a forgery, and the Iranian government denies any such plan.

The Iranian government has suspended the operations of the Arabic TV news channel al-Jazeera pending an investigation of charges its reports exacerbated the violence. The Qatar-based al-Jazeera has called the action unjustified and has urged Iranian authorities to reconsider.