World Health Organization investigators have asked to visit military hospitals in China's capital that are rumored to have patients with unreported cases of the deadly SARS virus, a group spokesman said Tuesday.

Such visits are a priority for the WHO team, which is looking into how health authorities in Beijing are handling severe acute respiratory syndrome, said spokesman James Palmer. But he said it wasn't clear when such a visit might take place.

"I think that's one of the big things that needs to be done," Palmer said.

Beijing has been rife with rumors of unreported cases at hospitals run by the secretive military. A prominent surgeon, Dr. Jiang Yanyong, said last week those facilities have more than 100 cases.

The highly contagious disease has killed 64 in China and sickened more than 1,300. Worldwide, there are more than 3,100 suspected cases of the disease and 144 deaths, mostly in Asia.

In Canada, health officials said a new cluster of 31 possible SARS cases involves members of a Roman Catholic religious community who attended the April 1 funeral of a victim of the illness.

Dr. Sheela Basrur, the chief medical officer of health in Toronto, said Monday some of the probable and suspected cases SARS in the cluster had previously been identified.

She said authorities figured out over the weekend that the 31 cases were linked, involving 29 members of the religious group, the BLD Covenant Community, and two doctors who came in contact with them.

Toronto, Canada's largest city located, is the epicenter of the largest outbreak of the illness outside of Asia. Most of the almost 300 probable and suspected cases in Canada have been in Toronto, including all 13 deaths reported so far.

In China, state media said Tuesday that a massive effort has been launched throughout China to disinfect buses, taxis and other public facilities in hopes of preventing new infections from the disease .

The WHO team has been visiting laboratories and hospitals in Beijing in hopes of finding ways to improve the city's handling of SARS, Palmer said. They are to meet Wednesday with Health Minister Zhang Wenkang, a former military doctor.

The team began its inspections last week after WHO cited failings by Beijing health authorities such as not tracing people who might have been exposed to those infected.

The Beijing Health Bureau had no comment Tuesday on possible WHO visits to military hospitals or other new measures.

Beijing announced 15 new SARS cases on Monday, bringing its total to 37. The capital has reported four deaths.

Most of China's 64 reported deaths have been in the southern province of Guangdong, where experts suspect the disease originated.

China accounts for about half of the more than 3,000 reported infections worldwide.

Health officials say numerous suspected SARS cases are under observation, but haven't given any details.

The official Xinhua News Agency reported late Monday that the city has mobilized 2,500 medical staff to visit homes of suspected SARS patients or those at high risk to the disease -- a possible indication that many more cases may be developing.

News reports Monday quoted Premier Wen Jiabao as calling for airline, train and boat passengers to be screened for SARS and quarantined if necessary.

At Beijing's West Railway Station, passengers are being screened for symptoms such as coughing, fever and shortness of breath and a quarantine room has been set up, the Xinhua News Agency said.

Windows at the station, which handles 50,000 passengers a day, have been opened to improve ventilation, Xinhua said.