SEOUL (AFP) - When hundreds of Yemenis arrived in South Korea seeking asylum after fleeing their war-torn country, opponents decried their Muslim religion and none of their applications were approved.

But an Iranian teenager who converted to Christianity has been granted refugee status.

Religious belief is widespread in South Korea, where crosses dot the skylines of cities and towns and, according to government figures, more than a quarter of the population describe themselves as Christians.

But the country is also ethnically homogenous and unwelcoming towards immigrants, and the decision in the Iranian's favour - a marked contrast to the norm - came only after a campaign by his classmates in Seoul.

The boy, who can be identified only by his adopted Christian name Antonio out of concerns for his safety, came to the South in 2010 as a seven-year-old with his businessman father.

Two years later, he became a Roman Catholic, and his father followed suit in 2015.

But their conversions infuriated relatives in Iran, where apostasy by a Muslim can be punishable by death.

The pair sought religious asylum in their new abode, but the South grants refugee status to only a tiny fraction of those who apply.

The world's 11th-biggest economy accepted just 708 refugees from 2000 to 2017 - a mere 3.5 per cent of total requests, one of the lowest rates in the world and far below the Organisation for Economic Cooperation and Development (OECD) average of 25 per cent.

Immigration authorities in Seoul rejected Antonio's asylum bid, arguing that he was too young to have religious faith, a decision upheld in May by the Supreme Court.

'RAY OF HOPE'

With Antonio facing the prospect of deportation to an uncertain fate, his classmates stepped in, launching a petition on the presidential website, describing his faith as sincere and saying he was still going to church.

A final chance to re-apply for asylum, they said, was "like a ray of hope from heaven".

With a GDP per capita of US$30,000 (S$41,000), they asked: "Could South Korea not embrace this one single soul?"

The petition was eventually signed by more than 30,000 people.

Around 50 students accompanied Antonio when he returned to the immigration office and they staged a sit-in for hours even as summer temperatures approached 40 deg C.

Many wore surgical masks to conceal their identities, with an anti-migrant outcry in full effect in South Korea after some 500 Yemenis arrived on the tourist island of Jeju earlier this year, taking advantage of its visa-free status to seek asylum.

Only around 4 per cent of the South's population are foreigners, mostly from China and South-east Asia, and discrimination against them is widespread.

Many opponents of the Yemenis' applications cited their Muslim religion, and nearly 70,000 people - a record - signed another presidential website petition urging the tightening of what are already some of the world's toughest refugee laws.

Social media commentators described the students as "brainwashed" and labelled them "crazy Muslim supporters".

"People threw all kinds of slurs and insults at us and our parents online, and some of us were a bit scared," said Antonio's classmate Choi Hyun-joon, who staged a protest in front of the presidential Blue House.

'NOT OUR PROBLEM?'

Critics complained to the school and city authorities, saying the establishment should remain neutral, said teacher Oh Heun-Rok.

"The very essence of education is to protect the dignity of humankind, and humanitarianism is a part of that," he told AFP.

Immigration authorities granted Antonio refugee status last month, two days after the Yemenis were turned down.

Both Antonio and his father declined to speak to AFP about the decision, not wanting to prejudice a forthcoming Supreme Court ruling on the father's own asylum application.

Ms Kim Yeon-ju, an activist at the Seoul-based Refugee Rights Centre, told AFP refugees generally get little support from South Korea's civic society, while a handful of Christians "may be a bit more willing to help".

"So Christian refugees may have better access to the services provided by these faith-based activists," she said, but it remains "very limited".

The unusual, high-profile campaign by Antonio's friends may have played a role in the decision on his application, she added.

During the drive, Antonio also met Seoul's cardinal Andrew Yeom Soo-jung, who vowed "all possible measures by the church" to help him, and wrote a prayer urging the authorities to give his case "special attention and consideration".

With Antonio's asylum approved, his classmates hope their efforts could encourage greater social tolerance toward refugees.

There was "no political or religious repression" in South Korea, they said in a statement, but asked: "Does that mean that we should just shut ourselves up, saying, 'Refugees are not our problem... Don't soil our home'?"