ISLAMABAD — Mohammad Hassan secluded himself in a religious seminary in Pakistan's largest city for 11 years until he memorized the more than 6,000 verses that make up the Quran, Islam's holy book.
Now the 27-year-old spends his nights at a computer in Islamabad teaching Muslims in the United States, Canada and Europe how to recite the Quran with the same Arabic pronunciation and intonation he believes the prophet Muhammad would have used.
"Read it correctly!" Hassan shouted at a teenager in Britain to whom he was talking over Skype, the online phone and video service. "You have been reading it for a long time now. Why aren't you reading it correctly?"
From thousands of miles away, Hassan and other online teachers have become a lifeline for some Western Muslims interested in studying Islam just as intensively as it is taught here in Pakistan, home to more than 100,000 mosques and more than 20,000 seminaries.
With lax telecommunications laws, a large pool of potential teachers and relatively new technologies such as Skype, Pakistan has become a global hub for computerized training courses on how to become a properly observant Muslim.
Business is booming, Pakistani entrepreneurs say, because there are not enough mosques and Muslim seminaries in the West to meet demand. And with the rise of the Islamic State — as well as a backlash against Islam in some Western nations — Muslim parents are more closely scrutinizing how and where their children are taught religion, they say.
"People in the U.S., Canada and U.K. are always telling us: We do have mosques, we do have proper setups, but we can never find one-on-one lessons," said Usman Zahoor Ahmed, 32, owner of ReadQuranOnline.com, where Hassan works. "And in this current atmosphere, they want to know what kind of teaching is being provided to their children — they want the lessons in their home, where mom or father is always watching."
Ahmed has a huge potential client base. The Pew Research Center estimates that the global Muslim population numbers 1.6 billion, with Islam on pace to become the world's biggest religion, eclipsing Christianity, by the end of the century.
By 2050, 10 percent of Europeans will be Muslim, according to estimates. The U.S. Muslim population is projected to double to 2 percent over the next 30 years, Pew concluded.
Eight years ago, Ahmed started his call center with two employees and just a few students. Now, he employs 22 teachers who work all night speaking to 320 students, about 40 percent of whom live in the United States.
Ahmed's brother Saqib, who helps run the call center, estimated that more than 50 similar centers operate in Pakistan, at least one of which has more than 1,000 students.
"I already got the education but now feel it's my service to spread it and teach it to others," said a teacher, Safeer Ahmed, 20.
Law enforcement officials in Europe and the United States have warned of the danger of Westerners becoming radicalized online. And December's terrorist attack in San Bernardino, Calif., where a Pakistani woman and her husband killed 14 people before being shot dead by police, has elevated concern about potential links between Islamic studies in Pakistan and terrorism.
Tashfeen Malik, one of the California shooters, had studied at a madrassa in the Pakistani city of Multan run by the Al-Huda Institute. The institute also conducts online training. But it's unclear whether Malik, who friends have said spent considerable time on a computer, also studied Islam online.
Usman Zahoor Ahmed said fears about online radicalization have little to do with legitimate Internet businesses that match students with online teachers for a tour through the "basics" of Islam.
For about $25, students get a 30-minute lesson five days a week. Initially, the lessons focus on the proper pronunciation of Quranic verses. There are also pictorial lessons on daily Muslim practice- praying five times, for example, and bending over to pray in such a way that a glass of water placed on the back would not tip.
The instruction then move to translating and interpreting the Quran, which requires eight years of daily lessons to fully comprehend, Ahmed said.
"If someone asks about jihad, which they rarely do, we would answer it with a strict interpretation of Islam," he said. "Jihad is something only allowed by a state — it's not an individual thing where someone can resort to a gun and take up weapons."
The Ahmed brothers run their business from the basement of Usman's house, using decade-old computers. About 11 each night, the teachers arrive, put on their headphones and begin calling students.
Flashing verses of the Quran onto students' screens, they work with each of their distant charges, syllable by syllable, teaching them how to properly recite specific verses, which to non-Muslims sound like short hymns.
"Stretch it out further, and don't shorten the word," Hassan told one struggling aspirant.
Shaukat Ullah Khattak, a religious scholar who runs a seminary in northwestern Pakistan, said such courses fulfill the spiritual needs of both students and teachers.
"It's mandatory for every Muslim to learn the Quran and spread it to others," Khattak said. "Online Quranic academies are doing great service . . . and kids in the West are now taking a keen interest."
Still, some question how common it is for Western Muslims to look overseas for Islamic instruction.
Edgar Hopida, spokesman for the Islamic Society of North America, said Muslims in the United States are focused on building their own educational institutions. Last year, he noted, Zaytuna College in Berkeley, Calif., became the first accredited U.S. Muslim college.
"We don't see people turning to Pakistan or other countries to learn the Quran," Hopida said. "It's easy to learn here in America."
But some Pakistanis are clearly profiting from online courses for Westerners.
The Ahmeds, for example, say they pull in $6,000 to $7,000 a month from their 320 students. They pay teachers $100 to $220 a month — or $1,200 to $2,640 annually — in a country where the average per-capita income is just $1,513 per year.
Most mornings, there are numerous classified ads in Pakistani newspapers seeking teachers for online Islamic study courses, some offering the option of working from home.
Jibran Ahmed recently quit his job as a teacher to open an online Islamic teaching institution.
"Our Muslim brothers abroad . . . face adverse circumstances these days," said Ahmed, 30, who is not related to the two brothers. "My academy and teachers will try to prepare better Muslims who can be of better use to the society that they live in."
Usman Zahoor Ahmed doesn't mind the increased competition.
"There will be 3 billion Muslims around the world [by 2100], and they are all our market," he said. "All you need is a computer, microphone, headset and Skype."
The Washington Post's Shaiq Hussain in Islamabad and Haq Nawaz Khan in Peshawar contributed to this report.