Law enforcement authorities in Northwest China's Xinjiang Uyghur Autonomous Region said they have taken note of online allegations that Uyghur girls were being telephoned and asked to serve as "sex slaves" for Islamic State (IS) jihadists in the Middle East, and are investigating the issue.

Such appeals were brought to public attention by a Sina Weibo entry posted on Sunday. The post claimed that some Uyghur students from Xinjiang, who are studying at high schools outside the region, have received anonymous phone calls. These appear to be soliciting them to give up studying to travel to Iraq to become sex slaves for IS fighters.

The post immediately caught wide attention and was reposted at least 2,000 times before it was deleted on Monday.

A source in Fujian Province, who claimed he had knowledge about such calls and would rather be identified as Zheng, told the Global Times that he was told by several Uyghur school girls about similar phone calls.

"They told me that they received anonymous calls, asking them to go to Syria through Indonesia for battlefield service. They were asked to dedicate themselves to jihadists. But the girls did not report this to the police. They were hesitant, because [they thought] all Muslims are brothers and sisters," Zheng noted.

Zheng added that the solicitation may expand from individuals to larger groups. "Many teenagers [studying outside Xinjiang] are from rural areas in southern Xinjiang. They are easily affected due to their family backgrounds," Zheng said.

Some Net users were shocked at the alleged instigation and called for attention from related authorities.

Website snapshots showed that the official Weibo account of the public security bureau of Altay prefecture in Xinjiang also retweeted the post, with a comment that it is following up on the issue. But the repost could not be found on the home page of the bureau's Weibo account Tuesday.

"It is possible that such calls do exist. One of our investigation focuses at present is how the students' numbers were leaked," a police officer from the Altay bureau, who didn't reveal his name, told the Global Times.

The officer added that before local students leave to attend schools outside the region, they all have to go through a training session.

"Such training is more about warning against participation in illegal religious activities, instead of being designed to guard against such calls, but I believe students will be highly alert if they receive such calls," said the officer.

Meanwhile, an anti-terrorism official in Xinjiang, who asked not to be named, Tuesday told the Global Times that authorities have taken note of similar online revelations, and are looking into the issue. However, this is yet to be confirmed.

Li Wei, an expert on anti-terrorism with the Chinese Institutes of Contemporary International Relations, said it would be very difficult to actually send those students out of the country, even if the alleged instigators are able to contact the students.

Sun Lizhou, a Xinjiang-born scholar from Chongqing University, told the Global Times that the authenticity of such calls still needs to be verified, "but since some Uyghurs are reportedly fighting alongside IS in Syria, it would be possible to speak to the students on the phone."

While this case cannot be verified for the moment, terrorist organizations seeking to split Xinjiang from China have long incited people in the region to join jihad both within the country and abroad.

"Religious extremism has misled people, particularly youngsters, into taking part in terrorist activities. Those deceived became chess pieces in a politically motivated plot," Nur Bekri, chairman of the regional government of Xinjiang, said in April.

Most of these efforts involve disseminating audio or video clips about provocative speeches, bloody scenes or burning national flags. Such content can be exchanged online or via memory cards. Some underground preaching sites, including home preaching, can also become a source for terror incitement, according to experts.

"Junior or senior high school students are an easy target of such incitement since they are psychologically immature and many are rebellious in their teenage years. A lack of objective judgment also makes them vulnerable to these audio or video files," Li added.

The anonymous anti-terrorism official in Xinjiang said that separatist groups tend to link themselves with overseas terrorist organizations, such as the IS, so as to boost their international standing, and win recognition from those groups in exchange for financial and personnel support.

The IS is also reportedly planning on expanding its "holy war" to Xinjiang.

According to a report from Phoenix Weekly, in a video released early July, IS leader Abu Bakr al-Baghdadi claimed he will take revenge on those who took away the rights of Muslims in 20 countries, with China allegedly placed at the top.

Experts pointed out that such vows are no more than a bluff. "This is the habitual practice of terrorist groups for propaganda efforts. It won't have any substantial influence," Li said.

Turgunjan Tursun, a research fellow from the Xinjiang Academy of Social Sciences, echoed such sentiments, but added that the IS may incite extremists in Xinjiang by spreading audio or video clips about extremism.