The heavy-handed response was a sign of the hard-line government's concern over any internal divisions amid its confrontation with the United States - and suggested there were worries the U.S. may try to stir up trouble among Iran's ethnic minorities.

The indefinite closure of the state-run Farsi language newspaper Iran came after it published a cartoon of a cockroach speaking Azeri, the language of Iran's largest ethnic minority.

Iranian officials quickly apologized for the slur and stressed the nation's unity in the standoff with Washington, which accuses Iran of seeking to develop nuclear weapons.

"It is clear that the evil hands of foreigners are making efforts to provoke tribal, ethnic, and religious differences under the present circumstances," State Public Prosecutor Ghorban Ali Dorri Najafabadi was quoted yesterday as saying by state media.

Hundreds of Azeris marched Monday in the northwestern city of Tabriz, protesting the cartoon. Some broke windows of the governor's office, and police used tear gas to disperse the demonstrators, witnesses said. Azeris, a Turkic ethnic group, make up about a quarter of Iran's 70 million people, dominated by ethnic Persians. Azeris speak a Turkic language shared by neighboring Azerbaijan.

They were angered by the cartoon run May 12 that suggested Azeris are stupid. It showed people from different walks of life -including an athlete and a tradesman - trying to teach the cockroach and he always answers, in Azeri, "What do you mean?"

There was no explanation why the protests broke out more than a week after the cartoon appeared.

Culture Minister Saffar Harrandi, speaking on state television Monday night, apologized for the drawing.

But Azeri legislator Eshrat Shayegh said the apology came "at least one week" too late.

Tehran Prosecutor Saeed Mortazavi announced yesterday on television that the paper's cartoonist and editor-in-chief had been detained.

"Those responsible, the cartoonist and the chief editor, were summoned, and the charges were read to them. The two were taken to Evin prison," Mortazavi said.

The daily, one of the country's top three newspapers, was closed "due to its publication of divisive and provocative materials," state television reported.

Iran saw a wave of newspaper closures amid the confrontation between reformers and hard-liners during the 1997-2005 presidency of reformist Mohammad Khatami. The hard-line judiciary shut more than 100 pro-reform newspapers and jailed dozens of editors and writers.

Ahmadinejad's government has taken no steps against the remaining two moderate newspapers that still publish.

Instead, yesterday's closure aimed to ensure national unity at a time when Iran takes seriously the possibility of U.S. military action over the nuclear issue.

Iran is a patchwork of many ethnic groups, but its numerous minorities have generally been quiet in past decades, with little overt show of opposition to the government.

But there have been worrisome signs.

A series of bomb attacks have occurred during the past year in Khuzestan, the center of Iran's Arab minority. An Iranian Arab insurgent group claimed responsibility for a Jan. 24 blast that killed six people and wounded 46. The Iranian government blamed the bombings on Britain and United States, which denied involvement.

In April, Iranian troops fired artillery and rockets at Iranian Kurdish guerrillas in Iraq amid reports they were crossing the border to infiltrate Iran's Kurdish minority.

Interior Minister Mostaf Pourmohammadi warned yesterday that opportunists are at work in Iran to inflame trouble.

"Some are misusing the situation. Others outside (Iran's) borders are trying to propagate protests through their satellite channels," he said in reference to U.S.-based Iranian opposition television channels.

"We should preserve our vigilance, especially the media . . . and not allow, under the current very important situation the country is in now, others who pursue certain intentions to misuse the situation," he said.

------ End of article

By ALI AKBAR DAREINI

The Associated Press