The Chinese government has reportedly blocked Microsoft's search engine Bing - the only global search platform that was open for use in the country, the company announced on Thursday.
According to a report in Financial Times, mainland Chinese users wrote on social media that attempts to access Bing's China site, cn.bing.com, failed.
"Two sources familiar with the government order confirmed that Bing had been blocked. One of the sources explained that China Unicom, one of China's major state-owned telecoms companies, had confirmed the government had ordered a block on Bing," said the report.
In a statement given to The New York Times, Microsoft said: "We've confirmed that Bing is currently inaccessible in China and are engaged to determine next steps".
According to Greatfire.org, a group that tracks what sites are blocked in China, said the site appeared to be inaccessible in parts of the country but reachable in others, reports The New York Times.
China's blockages often take time to spread nationwide, though in the past some services have been blocked in some places only to be restored later. It was not immediately clear why Bing has been being blocked.
China's internet regulator is yet to comment on the development.
Microsoft, which recently overtook Apple as the world's most valuable company, is the latest US tech giant to face difficulties in China.
Google Search is already inaccessible in China while Facebook-owned WhatsApp was blocked in 2017.
Google had earlier launched a search engine in China in 2006 but pulled the plug in 2010, citing Chinese government efforts to limit free speech and block websites.
Google has also shelved its plan to re-enter China through a censored search application code-named "Project Dragonfly" after massive protests.