The detention of four Iranian-Americans in Teheran on charges of spying has left many Iranian-Americans in the United States wondering whether visiting Iran this summer would be wise. Iranian-Americans, many of whom have dual citizenship, generally travel back to their native country with relative freedom despite periodic swells in tension and tough talk between Iran and the US But the recent arrests - including of a peace activist and an academic who were visiting their mothers - has some concerned that Iran is now targeting ordinary people. "When you have these arrests that come across as so arbitrary and unjustified, it does make everyone else very timid," said Trita Parsi, president of the Washington-based National Iranian-American Council. In late May, the State Department issued an updated travel warning to US citizens - and Iranian-Americans in particular - about potential harassment in Iran and trouble leaving the country. The warning, which cited the detentions, advised Iranian-Americans to "consider the risk of being targeted by authorities before planning to travel to Iran." Reaction among Iranian-Americans has been mixed. Some shrug off the warnings, saying these types of flare-ups between the countries have occurred before. But the detentions have been especially chilling for Iranian-American academics, many of whom have joined petitions protesting the case against Haleh Esfandiari, a Middle East scholar at the Washington-based Woodrow Wilson International Center for Scholars. Iran alleges that Esfandiari is part of a larger plot by the US to use scholars to foment a "soft" revolution in Iran, toppling the Islamic government by opening up Iran to the West. She and the other three Iranian-Americans face charges of endangering national security. Academics have postponed trips to Iran for fear of being detained, said Hamid Akbari, a professor of management at Northeast Illinois University and former executive director of the International Society for Iranian Studies. "Most Iranian scholars and activists are quite cautious at this time," Akbari wrote in an e-mail. Detained along with Esfandiari are Kian Tajbakhsh with George Soros' Open Society Institute, and Ali Shakeri, a peace activist and founding board member at the University of California, Irvine, Center for Citizen Peace building. Journalist Parnaz Azima from the US-funded Radio Farda is out of jail on bail but not allowed to leave the country. An Iranian judiciary spokesman said last week that a judge would soon decide whether they will be indicted or released. The 2000 Census estimated that there were 330,000 Americans of Iranian descent living in the US. Many came around the time of the Iranian Revolution, which culminated in the 1979 toppling of the Shah of Iran and the establishment of a theocratic government. They include the shah's son, Reza Pahlavi, who lives near Washington. Esfandiari was visiting her 93-year-old mother in Teheran when she was taken into custody. And the summer school vacation is a time when some Iranian families take their children back to see family. "I don't know of anybody who is planning to go that has canceled because of this," said Hossein Hosseini, a former board member of the Network of Iranian American Professionals of Orange County. "The summer season is pretty big with a lot of people in the community." Even those who left for political reasons still maintain their Iranian citizenship, which must be formally renounced under Iranian law. It means Iranian-Americans can enter Iran without a visa, making travel easier. But the country's hard-line government also used it as a pretext to detain the four Iranian-Americans, saying they are subject to that nation's laws despite their American citizenship. The detentions have prompted speculation, said Hossein Hejdazi, the program director and talk show host at the Los Angeles Farsi radio station KIRN-AM. Theories being bandied about include that Iran is using the prisoners as a bargaining chip because of the American military's detention of Iranians found in Iraq, or Iranian suspicion of a $75 million (â‚¬56 million) State Department program to encourage democracy in Iran. Hejdazi says he is urging Iranian-Americans to be cautious about going to Iran. "We are telling people don't just go if it is not urgent," he said. "Postpone it until we can see what direction it goes."