Russia has confirmed its first case of Severe Acute Respiratory Syndrome.
Doctors in far east Russia say medical tests show that a 25-year-old man who has been under observation for weeks has the potentially deadly virus.
The man was staying in a hotel in the town of Blagoveshchensk near Russia's long border with China. The hotel is frequented by Chinese traders who come into Russia to sell their products.
Officials quarantined the hotel when the suspected case was first reported, sparking fears that SARS was spreading into Russia from China, the country worst affected by the outbreak.
Most of Russia's border crossings with China are closed, and airlines have suspended flights between the two countries in an effort to stop the disease from spreading.
Prime Minister Mikhail Kasyanov has met with top health officials to discuss other measures, including spot medical checks on passengers arriving from China by indirect routes.
Russian doctors are checking train passengers who might have fevers or show other symptoms of the disease.
Chinese President Hu Jintao is making an official visit to Russia. On Tuesday, Mr. Hu raised the issue of SARS in talks with Russian President Vladimir Putin.
Mr. Hu pledged that China would do all it can to contain the spread of the disease, which has killed more than 740 people and infected thousands of others around the world in the past few months.
In a speech at a Moscow university, Mr. Hu also said he is confident that China will maintain its steady rate of economic growth, despite the SARS problem.
Mr. Hu is on his first foreign tour since he assumed the Chinese presidency in March.