Health authorities are cracking down on surrogate-birth services by stepping up efforts to hunt down and stop anyone advertising such services online.

In Beijing, more than 8,000 such postings have been removed from a wide range of websites since April.

In Shanghai, the Health Department has paid close attention to the advertising of 97 media organizations to prevent surrogacy ads, the national working group on fighting surrogacy said in a statement published on Thursday.

The China Food and Drug Administration has launched an operation to keep companies that produce assisted reproductive equipment and drugs under surveillance and prevent them from selling products to unlicensed agencies and personnel, according to the statement.

The Ministry of Public Security asked police departments nationwide to take a tough line on surrogacy, and 58 hospitals affiliated with armed police departments were ordered to avoid surrogate pregnancy cases, it said.

The recently established group, led by the National Health and Family Planning Commission and consisting of 11 members of ministries and state organizations, said the results, achieved since the campaign began in April, were commendable.

On April 8, the group published guidelines for the campaign, saying, "Surrogacy upsets the natural order of childbirth and poses potential health risks."

Individuals and business entities are prohibited from having any role in offering or promoting surrogate-birth services.

Although China has no surrogacy law, the trade in fertilized eggs and embryos was outlawed in 2001. Additionally, hospitals were prohibited from assisting in surrogate-pregnancy cases.

However, the service is rampant underground through advertising on the Internet, as infertility is on the rise nationwide.

According to Caixin Online, a 2012 study by the China Woman and Child Development Center and the China Population Association found that about 12 percent of Chinese women of childbearing age were infertile. The figure two decades earlier was 3 percent.

In Beijing alone, more than 20,000 couples underwent legal in vitro fertilization in 2012, resulting in the births of about 5,000 babies, according to the capital's Health Bureau.

The national working group said that dealing with the frozen eggs and embryos seized from the illegal business remains a problem, adding that relevant laws and regulations should be in place to cope with the situation.