The echo of Moscow's theater siege reverberated loudly in the unheated, unfinished mosque where Zvenigorod's 500 Muslims come to pray. Two Central Asian men, sitting here wrapped in coats against the winter chill, heard it in the hatred of the town drunks and the scorn of the militia, which confiscated their passports and vowed to kick them out of the country.

It didn't matter that they had nothing to do with the Chechen guerrillas who stormed the theater in October, that they barely know how to stumble through their own prayers to Allah, much less embrace the brand of militant Islam adopted by terrorist groups waging war on the West. They, too, were the enemy.

"When we say we are Muslim, they humiliate us," said Rustam, a 45-year-old laborer from Tajikistan, who is afraid to give his last name because the local police detained him after the theater incident and demanded that he pay 500 rubles or leave the country.

Yakub Valiullin, the imam who has struggled to build this tiny outpost of Islam on the outskirts of the Moscow region, nodded in sad agreement. After the theater siege, he found himself answering questions from the Federal Security Service (FSB) about the Muslims in his congregation. Even now, he is guarding these two Central Asian men, hoping to stop their deportation. "They say, 'You Muslims kill people,' " he said.

"They equate all Muslims with terrorists."

Such "Islamophobia," as it has become known here in Russia, has divided and overwhelmed what by the numbers should be the country's most influential minority. Muslims are the largest religious group in Russia after the Russian Orthodox and have a centuries-long tradition here. Technically, they are more numerous and more free than ever in their history in Russia, and after 70 years of state-sponsored atheism there has been a Muslim renaissance in the last decade, with a major program of mosque-building and thousands rediscovering the rituals of their grandparents' generation.

But along with revival has come insecurity for Zvenigorod's Muslims -- and many others among Russia's estimated 20 million followers of Islam -- who say they are experiencing a rebirth of the fear they hoped they had left behind with the Soviet past. This fear has flared repeatedly in the post-Soviet decade, ebbing and flowing with Russia's war against the predominantly Muslim breakaway republic of Chechnya, and returning, stronger than ever, after the Sept. 11, 2001, terrorist attacks against the United States and the Moscow theater siege.

"These events have only strengthened the hand of the large group in Russian society who were already hostile to Islam and considered Islam to be the ideology of terrorism," said Robert Landa, a professor at Moscow's Institute of Oriental Studies.

Sometimes, the fear comes as a tangible threat, such as the imminent expulsion faced by the two Central Asian construction workers in retaliation for a terrorist act they are linked to only by their religion. Just as often, it is an abstract anxiety, the feeling that at any moment the authorities can close down the mosque.

"It's very hard for Muslims to live here now," said Valiullin. "In Russia we have this problem -- we are always looking for an enemy. It used to be the Jews, now they have all gone to Israel. So the politicians see the Muslims -- we are poor, we have no power. Instead of Jews, they attack Muslims. They incite the crowd. 'Beat the Muslims!' We are the new Jews."

Russia's Islamophobia has taken on many forms, from violence, like the skinhead rampage in a crowded Moscow market last year allegedly aimed at "persons of Muslim nationality," to newspapers that run pictures of local Muslim leaders next to photographs of Osama bin Laden. Human rights groups have reported an upsurge in hate crimes throughout Russia, some related to ethnicity, others connected more directly with the presumed Islamic heritage of the victim.

President Vladimir Putin has tried to speak judiciously, often repeating that Islam is a peaceful religion not synonymous with terrorism. But at times he has used inflammatory rhetoric, suggesting that the conflict in Chechnya is part of a broader war between Islam and Christianity. "If you are a Christian, you are in danger," he told a French reporter last month, before suggesting to the reporter that he be circumcised.

More than anything else, a single word -- much invoked, much misunderstood -- has come to symbolize what Muslim leaders say is the demonization of their religion here.

It is "Wahhabism," which technically refers to the austere form of Islam practiced in Saudi Arabia. In Russia, where a moderate brand of Sunni Islam has been the traditional faith, the alleged importation of Wahhabism has come to mean something akin to "terrorism," and is the most damaging charge one can hurl against a religious Muslim here short of accusing him of treason.

The Chechen rebels are regularly accused of Wahhabism, and Russian news media routinely raise the alarm, as the news agency Interfax did the other day with a story headlined: "Russia sees rise of Wahhabism." The FSB often confiscates Islamic religious material -- even copies of the Koran -- as seditious "Wahhabite" literature, according to interviews with a half-dozen Muslim clerics who separately said they had witnessed such incidents.

And the term has become a convenient rubric applied to Muslims whose work offends authorities. Farid Nugumanov, for one, found himself under investigation by the FSB for his alleged Wahhabite sympathies. Nugumanov, a journalist in the Orenburg region, had published an article criticizing the decision to build an Orthodox church next to the Muslim cemetery in his majority-Muslim village. He not only lost the job he had held for 16 years, but also found himself publicly labeled "the Wahhabi."

"That's the way it goes in our region -- whoever does not support the authorities is a Wahhabi," he said. "Just like in Stalin's times, we are all considered 'suspicious' now just for going to the mosque."

For Russia's Muslim leaders, such incidents offer proof of religiously motivated bias. "Why must we use religious terminology like Wahhabism? If someone is a terrorist, call it terrorism. But why call him a Wahhabite? We don't call Irish terrorists Christians. They're just terrorists," said Nafigulla Ashirov, the chief mufti for the Asian part of Russia.

Ashirov has a fat file of his press clippings. One shows his picture next to bin Laden's. Another, in the prominent newspaper Nezavisimaya Gazeta, calls him "an accomplice of terrorism." Ashirov courted controversy by criticizing last year's U.S.-led war to overturn the strict Taliban regime in Afghanistan, but he insisted he is no Wahhabi.

"This is a specific policy in Russia working here to discredit Islam," Ashirov said. "Today there is no uniting ideology like communism, so they have painted a new enemy, Islam. It is not safe for Muslims to be in Russia today."

But it is not just unbelievers wielding the term "Wahhabite" as a weapon against religious Muslims.

A long-running feud between the two top Muslim spiritual leaders in the country has contributed as much as anything to the public concern about Wahhabism. Talgat Tadzhuddin is a veteran of the Soviet-era religious bureaucracy, presiding over the Central Spiritual Directorate of Muslims from his headquarters in the Muslim region of Bashkortostan. Ravil Gainutdin leads the rival, Moscow-based Council of Muftis, a post-Soviet group now claiming the adherence of a majority of Muslim congregations.

Each uses the charge of "Wahhabism" to undermine the other.

"Some people are trying to represent this as a standoff between clerics and a struggle for power and property and funds," Tadzhuddin said. "But we can't accept this other group's support of spreading Wahhabism in our country. They are spreading religious extremism, fanaticism, blood and tears."

Just days ago, Tadzhuddin gathered dozens of his adherents for a conference where they warned darkly that there are already more than 100,000 Wahhabites in Russia, a "heretical" group aided by his rival, Gainutdin. The claim, entirely unsubstantiated, made national news.

For his part, Gainutdin is perhaps best known for holding a news conference after Sept. 11, 2001, where he brandished a picture of Tadzhuddin standing next to bin Laden's brother. He failed to mention that the meeting had taken place a dozen years ago as part of an official Saudi delegation to Russia.

"I know for a fact he has received thousands of dollars from those he now calls Wahhabites," Gainutdin said. "When he calls me a Wahhabite, he knows well this is not true. It's his defense to keep himself at the top of Islam in Russia."

Either way, the feud has served as a convenient method of ensuring that Russia's Muslims do not secure the political clout that their numbers would seem to warrant. Both sides suggest that a very familiar Soviet-era tactic has been employed to fuel the rivalry.

"This division is in the interests of the state," Gainutdin said. "There are people in the government who are not interested in Muslim unification, because 20 million people is a whole country and a very serious force. So of course they are afraid of a united Muslim community. It's useful to divide and rule."

Here in tiny Zvenigorod, where Muslims have coexisted with their Russian Orthodox neighbors since 1497, the power plays of leaders might not mean much in a mosque without heat, but the strong hand of the government routinely reaches inside the modest red-brick building.

Valiullin, the imam, said the FSB often comes to demand information, asking questions that themselves are revealing about the prevailing attitude toward Islam.

"They want to know if I am hiding guns here," he said, gesturing to the two spartan rooms that constitute the mosque he has been building since 1999. "They ask me, 'Are you teaching terrorism in the mosque?' "

Often, Valiullin said, the Muslims here compare today's problems to the different sort of fear that governed them in Soviet times. Valiullin's 87-year-old mother, Zainab, is a living connection to the old kind of fear, the kind that destroyed mosques and drove prayers underground.

As a child, she witnessed the Communists torching the mosque where her forefathers had prayed. "They threw the religious books into the river. My father picked them up out of the water -- a whole cart full of them," she recalled. He hid them in their attic.

Today's problems are less extreme. But, said Valiullin, "We are still afraid. It can take only five minutes to shut down this congregation. They can plant drugs here, or 'terrorist' literature. They can call us Wahhabites, and solve the problem of Islam in Russia in this very simple way."

Many Russian Muslims compare their fear today to that felt in Soviet times. With Imam Yakub Valiullin is his mother, Zainab, who saw a mosque destroyed.