“Russia’s greatest demographic challenge could well be integrating its rapidly growing ethnic Muslim population in the face of a shrinking ethnic Russian population,” the report said. The changing ethnic mix “already appears to be a source of growing social tensions.”

By the most conservative estimates, 2 million Muslims now live in Moscow, a city of nearly 12 million.

Polls show that nearly half of Russians dislike migrants from Central Asia and Russia’s Caucasus — another source of Muslim migration. They have become the bogeymen of Russian nationalists, accused of stealing jobs, forming ethnic gangs and disrespecting Russian customs.

“If you build a mosque in downtown Moscow, slaughter sheep on your holiday and impose your traditions on us, no one will want you as a neighbor,” said Dmitry Demushkin, a veteran Russian neo-Nazi skinhead who heads a nationalist party.

Central Asian labor migrants for years have filled the lowest paying jobs, working as janitors, street cleaners, construction workers, vendors at outdoor markets and unlicensed cab drivers whose run-down cars are popularly known as “jihad taxis.” Many live in trailers on construction sites, in squalid basements and overcrowded flophouses or sleep inside their cars. The uncertain legal status of many of the migrant workers has left them vulnerable to abuse and exploitation from employers. They also have fallen victim to xenophobic attacks.

But in recent years, they are increasingly becoming more established members of the work force. And a significant minority, like Bulgakov, now run their own successful businesses.

The undisputed star among Russia’s Central Asian business figures is ethnic Uzbek Alisher Usmanov: His interests in mining, telecoms and Internet startups have made him one of Russia’s richest men, with a fortune estimated at $18.1 billion, and he is the co-owner of British soccer club Arsenal.

Filmmaker Timur Bekmambetov, who was born in Kazakhstan and educated in Uzbekistan, has directed some of Russia’s most top grossing movies. Recently he moved to Hollywood, directing this year’s “Abraham Lincoln: Vampire Hunter” and before that “Wanted,” a 2008 action flick with Angelina Jolie.

Uzbek native Mirzakarim Norbekov has penned half a dozen bestsellers based on the medical teachings of Muslim medieval scholar Avicenna, who was born in what is now Uzbekistan. His medical training center in Moscow charges hundreds of dollars for short healing courses.

And while the Central Asian influx has caused frictions, there are also abundant signs of non-Muslim Muscovites embracing things seen as quintessentially Central Asian. Uzbek restaurants, fast-food joints and clay-oven bakeries that churn out round flat-cakes and meat pies have become ubiquitous; fashionistas sport oriental silk scarves and pashminas that resemble hijabs; and many ethnic Russian housewives buy halal meat believing it to be healthy and devoid of chemical preservatives.

The trend may have deep roots in Russian history: Unlike most West European capitals, Moscow has absorbed Muslims into its population for centuries.

The principality of Moscow emerged as a regional power some 700 years ago, when the Golden Horde, a state dominated by Mongols and Muslim Tatars, controlled parts of what is now southern Russia, the Caucasus and Central Asia. As Moscow took over the Horde’s territories and invaded lands that once had been conquered by Arabs, Persians and Turks, Muslim nobles became part of the Russian elite and Muslims were free to practice their faith under the czars.

Novelist Vladimir Nabokov proudly wrote that his aristocratic family descended from Nabak, an illegitimate son of Genghis Khan. Composer Sergei Rachmaninoff and writer Mikhail Bulgakov were the offspring of Tatar nobles.

“Muslims are not newcomers here, and all the current problems are temporary,” said Vladilen Bokov, a devout Muslim and member of the Public Chamber, which advises the Kremlin on social issues.

The Central Asians are far from a homogeneous group: Kyrgyz are proud of their militant nomadic heritage, while Uzbeks and Tajiks extol their cultures that produced poets and scholars who contributed to medieval Muslim civilization.

Czarist armies finished the conquest of Central Asia by early 20th century and Stalinist purges decimated their elites. The Soviet era reshaped their economies and agriculture and made “Russification” a key to success for several generations of their best and brightest. In the 1980s, Central Asian conscripts became a majority in the Soviet Army as birth rates among ethnic Russians plummeted.

Communist Moscow tried to win sympathies of Central Asians — and uproot their Muslim traditions — by building schools and universities. Their graduates are still qualified to work as bank clerks, computer engineers, artists and medical doctors in Russia. Employers often praise them for their hard work, career ambitions and indifference to alcohol — Russia’s proverbial scourge.

The 1991 Soviet collapse was followed in their overpopulated republics by ineffective economic reforms, political unrest a resurgence of Islamic traditions and a gradual loss of Soviet mentality. But the number of Russian speakers remains high. They visit Russia visa-free and can stay here for up to three months, or longer if they get work or residence permits.

Construction company owner Bulgakov has faced his share of hardships.

Square-jawed and burly, he recalled over a cup of steaming tea how he stole some undercooked buckwheat from a dormitory kitchen several days after losing a job. He lost another job after beating up his supervisor for calling him a “churka,” a pejorative term for Central Asians. Bulgakov said that during a hospital visit he heard a doctor reproaching his ethnic Russian wife for failing to “find a decent Russian man.”

After several years of selling construction paint, Bulgakov started his own company.

Now his company renovates apartments of affluent Muscovites and works on occasional contracts with the Defense Ministry. He also has joined Kremlin’s United Russia party and wants to run for office in the Moscow suburb of Ivanteevka where he lives with his wife and two children.

Bulgakov, who sports a white-gold ring with a sparkling diamond, has this advice for fellow Central Asians seeking a better life in Moscow.

“If you want to work, just work,” he said, “If you don’t, you’ll find a thousand excuses — ‘I am being oppressed, abused, beaten.’”