Washington (CNN) -- As demonstrations are staged in Syria against President Bashar al-Assad, protests against the regime also are taking place in the United States, organized by Syrian-American and Syrian activists.
Some of the U.S. demonstrators say that personnel from the Syrian Embassy in Washington have been photographing them and using the photos to intimidate them and to harass their families in Syria.
The State Department said Thursday it is taking those allegations seriously and confirmed that it had seen reports that Syrian Embassy officials were carrying out photo and video surveillance of protesters in the United States. The department said it is investigating reports that the Syrian government had sought retribution against the demonstrators' families in Syria.
On July 6, State Assistant Secretary for Diplomatic Security Eric Boswell called in the Syrian ambassador, Imad Moustapha, to discuss reports that his staff was spying on peaceful demonstrators in the United States.
A law enforcement official told CNN that FBI agents have been meeting with Syrian activists in the Washington area for several weeks. In those conversations, the official said, the FBI expressed concerns about the activists' safety and offered suggestions on how they can watch out for their safety.
The official would not confirm the identities of the activists with whom the FBI has met, adding that U.S. officials had seen no evidence of a credible threat but were continuing to look into the matter.
The Syrian ambassador was out of the United States and not available for an interview with CNN; the embassy's press attache would not comment on the issue. A Syrian source with knowledge of the issue who spoke on background to CNN because of the sensitive nature of the matter would neither confirm nor deny that embassy staff had been photographing demonstrators in the United States but expressed skepticism that that has happened.
The protests, he said, are posted on YouTube and Facebook and available to anyone who wants to watch them. "Why would you need to use spies?" he asked.
Hamdi Rifai, a New York lawyer and a Syrian-American activist who heads the group Arab Americans for Democracy in Syria, has complained to the State Department about the intimidation.
He said he has felt the long arm of the Syrian government, including a letter from a branch of a government ministry expressing disapproval of his activities.
"The regime has made it very clear that they feel they can control us," Rifai said. "Even before the revolution, I had never attended a public social gathering where the ambassador or embassy staff were not present. They were always present -- making sure we stayed in line."
Now, he said, Syrian authorities in the United States are involved in organizing pro-government protests and monitoring the demonstrations of the anti-government people.
Rifai said there are three political groupings of Syrians in the United States: those who are actively supporting the revolution; the fence-sitters who refuse to acknowledge the ferment; and the supporters of al-Assad.
Fear pervades the community, he said. Rifai said one of his relatives in the United States, a former government employee in Syria, routinely warns of the dangers of activism.
Rifai said some family members in Syria have "unfriended" him on Facebook lest they be tainted by their association with him.
Rifai said it would be dangerous for him to return to Syria. "I'm not afraid in the United States," he said.
Radwan Ziadeh, a Syrian human rights activist and visiting scholar at George Washington University in Washington, told CNN the FBI called him after his friends told the bureau they had received anonymous "threat calls."
"The FBI, they phoned me twice or three times. They need more information about what's going on the country, what kind of threat level here, and they have some concerns about the safety of Syrians here," he said.
Ziadeh said that, after one demonstration, he was invited to go to the Syrian Embassy for "some discussion." When he arrived, "I (was) surprised that two persons inside the embassy taking pictures of me inside the embassy."
The activist said he believes the photos were passed on to Syrian intelligence in Damascus, but has no proof.
Ziadeh added that he had been receiving threats against his relatives in Damascus through his Facebook site, through e-mail and by phone.
"Always I have concern about my mother because sometimes she is hiding," he said. "My brothers, they cannot actually move very freely. ... They arrest four of my cousins because they participate in demonstrations in Damascus and always they ask them questions about their relationship with me, if they are in communication with me here in Washington."