Ever since the first mosque opened in Harrisonburg, Va., 14 years ago, the immigrants from Pakistan, Iraq and other countries who worship there say they have felt welcomed in the rural college town. They participate in local food banks and shelter programs, have close relations with local churches and often receive non-Muslim visitors at their weekly prayer services.

So on Friday, worshipers were shocked when they arrived at the mosque to find graffiti scrawled on the building, including obscene and racial insults against “Irakis” and a warning: “This is America,” followed by another slur. Some speculated that the sudden harassment must have sprung from the anti-American violence that has swept the Middle East over a vulgar anti-Muslim video made in the United States.

“Nothing like this has ever happened to us before, even after 9/11,” said Ehsan Ahmed, a director of the Islamic Center of Harrisonburg mosque and an economics professor at nearby James Madison University. “We have always been welcomed here, and we participate in many community activities. We can’t say what their motive was, but the timing is very coincidental.”

On Saturday morning, members of the Dar al Hijrah Mosque in Falls Church emerged from an early prayer service to find that someone had smashed the windows of about 30 cars parked on neighborhood streets. No written slogans were left, but mosque officials initially thought the vandalism was directed at them.

Later in the afternoon, a Fairfax County police spokeswoman said the incident was a “random act of vandalism” that was scattered over a widespread area and that “the mosque was not at all the target.”

Men gather for prayer at the Dar al-Hijrah Mosque on Aug 12, 2011, in Falls Church. Members of the mosque emerged from an early prayer service Saturday to find that someone had smashed out the front and back windows of about 30 cars. (Jahi Chikwendiu/WASHINGTON POST)

Over the past several days, Muslim leaders in the Washington area and across the nation have rushed to denounce the vulgar video and the anti-American violence it has provoked.

American Muslim immigrants have taken the furor in stride, saying they refuse to be provoked or exploited by extremist forces on either side.

In Harrisonburg, members of the vandalized mosque said they were immediately bolstered by sympathetic support from the community. A city council member hastily set up a Web site called “We are all Harrisonburg” and invited residents to attend a solidarity meeting at the mosque Sunday. More than 500 people signed up.

“This incident has given people an opportunity to reach out and get to know their neighbors, to build something positive from it,” said Kai Degner, the council member and a real estate agent. “Our city is growing and changing and becoming more diverse, with 57 languages in our schools. Change can require adjustment, but we have had no horror stories here.”

Mohammed Aslam Afridi, a Pakistani-born veterinarian who is president of the mosque, said he was sure the graffiti was connected to recent events elsewhere. “This anti-Islamic video has stirred people up, and so has the attack on the Sikh temple in Wisconsin,” he said. “People are angry and upset. But we are all children of Adam. This is my Harrisonburg, my Virginia and my country.”

Leaders of other mosques and Muslim organizations have been working overtime all week to call for calm and to make sure the provocative video, which portrays the Prophet Mohammed as a salacious thug, does not create new tensions or clashes for their communities. An estimated 5 million foreign-origin Muslims reside, work or study in the United States.

On Friday, Imam Mohamed Magid told worshipers at the All Dulles American Muslim Society, a large and influential mosque in Sterling, not to allow the provocative video — believed to have been made and promoted by a few extremist Coptic Christian immigrants from Egypt — to undermine the image of their faith community and damage the relationship between the United States and the Islamic world.

“We should not fall into the trap of people who want to portray Muslims as violent people,” Magid told the congregation. “We should not express our anger with violence and breaking things and taking innocent people’s lives,” Magid said. Instead, he called on Muslims to combat bigotry with education. He also paid tribute to the U.S. ambassador to Libya who died Tuesday in an assault on the U.S. Consulate there.

Leaders at Dar al-Hijrah joined a news conference Wednesday condemning anti-American violence in Libya and Egypt and later went to a prayer vigil in front of the White House. Residents in the surrounding neighborhood expressed suprise and concern when they heard about the vandalism.

“Oh, dear. I was worried something like this would happen,” said Kathleen Kline Moore, pastor of the First Christian Church of Falls Church, one block away. “These people are our friends, and we always let them park in our church lot on Fridays. We support them and we absolutely deplore what has happened to them.”

On Saturday, the Washington-based Council on American Islamic Relations issued a video appeal in Arabic by its executive director, Nihad Awad, asking Muslims not to blame the U.S. goverment for the video.

Awad and Magid said they had given numerous interviews this week in an effort to calm tensions and counteract misinformation about the video. On Friday, Awad participated in a debate on an Egyptian satellite news channel with organizers of the protests there.

Among many Muslim immigrants in the Washington region, there was a similar expression of revulsion against the video and horror at the convulsive violence that swept the Middle East in response. Several said they feared that the episode would revive the kind of suspicion and hostility that affected their communities after the Sept. 11, 2001, terrorist attacks. Others said the inflammatory video should have been taken off YouTube and other Internet sites where millions of Muslims could see it.

“Both sides are wrong. The video was disgusting, and the violence was totally wrong,” said Zahid Mughal, 38, a Pakistani American who runs a gas station in Arlington County. “Any fool can put a video on YouTube, and by reacting so violently, you just give the extremists what they want.”