Microsoft Inc. (MSFT) - Get Report said Thursday that authorities in China have blocked access to its Bing search engine, marking what could be the end of foreign-backed portals inside the world's second largest economy.

Microsoft's confirmation of the blockage leaves all major search engines in China owned or controlled domestically, with Baidu Inc. (BIDU) - Get Report  dominating the world's biggest online market. The decision, which hasn't been officially confirmed by the powerful Cyberspace Administration of China (CAC), may also complicate reported plans by Google parent Alphabet (GOOGL) - Get Report to launch a new censored search engine that would block certain search terms linked to human rights, democracy and religion.

The new search engine, code-named "Dragonfly", could allow Google to make deeper inroads into China, where its main platforms, including YouTube, are blocked by the CAC.

Microsoft shares were marked 0.44% higher in pre-market trading at $107 each, while Google shares were indicated 0.24% higher at $1,087.00 each. Baidu's U.S.-listed shares slipped 0.15% to $163.01 each.

Alphabet CEO Sundar Pichai told U.S. lawmakers last month that, "right now (Google) has no plans to launch search in China", where its main engine has been blocked since 2010. However, he added that Google had about 100 people working on a project that looked at "what search could look like" in the China market.