Every Thursday night, the music of a tanbour, a long-necked stringed instrument, resounds across the wooden floors of a Manhattan room, wrapped with warm Persian rugs. Barefoot men and women create circles and sway to the cadence of the melody.

The music builds as their teacher, Sheikha Fariha, joins the circle. She slowly begins to spin and passes by each individual, looking into their eyes and breathing on their faces, while repeating variants of the names of God. The words are Arabic but she does not have the accent of a native speaker. Soon the faithful are making circles, whirling.

This scene unfolds in New York City’s TriBeCa district, 12 blocks away from ground zero. It reflects the popularity of Sufism, Islam’s mystical tradition, whose appeal seems to grow among a segment of spiritual seekers even as the faith’s mainstream varieties arouse antipathy among swathes of the American public. (A new study by scholars at the University of Minnesota found that Islam has surpassed atheism as the metaphysical belief disliked by the greatest number of Americans.)

The very word Sufism can be confusing: correctly or otherwise, it is used to describe a broad range of practices and beliefs, all of which involve the pursuit of a direct experience of the divine. It can refer to the popular religion of Pakistan, with its emphasis on saints and shrines, or to powerful Islamic thinkers and mystics of the medieval era whose ideas have always drawn in a steady trickle of well-educated Westerners.

In the United States and many other places, self-identified Sufis can be Muslims who are very orthodox in their beliefs and observances, or people who are not Muslim at all but are attracted by Sufi music, dance or meditation.

The community in lower Manhattan is towards the liberal end of that spectrum, but not at the far end. On one hand, it has distinguished Islamic connections. It is affiliated with a Sufi order established by a famous teacher from Istanbul, Muzaffer Ozak, who came to the United States in 1980. But the participants in its rituals include both people of Muslim background and non-Muslim spiritual seekers. The place attracts around 100 regular attenders; about 20 new members join every year.

Over the centuries, travelling Sufis have always been among Islam’s most powerful ambassadors. They brought the faith to the Indian subcontinent and to present-day Indonesia. And Sufis have been present in the New World for many centuries, pre-dating Christopher Columbus, according to Julianne Hazen, a professor at Niagara University who studies American Sufism. Later, at least 15% of slaves brought from Africa were Muslims, and some of them were Sufi.

Then in the early 1900s, a Sufi master called Inayat Khan travelled through North America and established at least 13 communities who followed his mystical path. Since then, virtually every major Sufi movement in the Old World has established itself on American soil.

Sheikh Muzaffer, the Turkish-born teacher who was ultimately responsible for the mosque in lower Manhattan, is only one example. On arrival in America, he was welcomed by devotees of the great Sufi poet Rumi and became a popular figure at spiritual gatherings. At one of them he met and influenced Philippa de Menil, a member of a famous Franco-American family of art patrons, and her German-born husband. Both pupils received new Sufi names. Sheikha Fariha, who took over the leadership of the lower Manhattan community after her husband’s death in 1995, is the Muslim name of Ms de Menil.

In their backgrounds and reasons for joining, the people who come to whirl are almost as diverse as Manhattan itself. “I’ve always liked people who want to be surrounded by a certain amount of love. This is why I joined this circle, and Sheikha Fariha makes my stay easier,” says a woman who uses the Sufi name Hafiza.

A fellow participant, a 34-year-old technology consultant, says she was drawn to Sufism by the writing of Rumi, as well as by whirling workshops organized by a former flamenco dance instructor who uses the Sufi name Sakina. “Dancing is part of my self-expression,” adds this tech-minded whirler. “No wonder I was drawn to this religion.”

In contrast with most other forms of Islamic ritual, male participants in the community say they have no difficulty in taking guidance from a woman. “She is just someone who has walked the path before me, it could be a man, it could be a woman,” said a 59-year-old man.

One female member, who uses the Sufi name Nafisa, is originally a Shia Muslim from India. When she moved to New York, a friend invited her to try this branch of Islam. Because of its “progressivism,” she said, friends back home told her that American Sufis were “fake worshippers” because of their non-traditional approach. But it seems to suit her.

All the participants stressed that what they are following is a real spiritual calling, not just a fad. People who turn up at the mosque will vary in their level of commitment but it soon becomes clear what their real intentions are.

As the conversation dies down, Sheikha Fariha re-forms the circle and invites the congregants to rest their minds. “La illaha illa Allah,” they chant in unison. “There is no other god but God.”