China's ambassador to the UK has called Britain's decision to ban telecoms giant Huawei from its 5G network "disappointing and wrong".
The UK government has ordered companies to strip equipment from Huawei out of the system by 2027.
It follows sanctions imposed by the US, which claims the Chinese firm poses a national security threat - something Huawei denies.
US President Trump welcomed the UK decision, calling Huawei "unsafe".
"We convinced many countries, many countries - and I did this myself for the most part - not to use Huawei because we think it's an unsafe security risk, it's a big security risk," he said.
Mr Trump made the comments as he attempted to increase pressure on Beijing by announcing an executive order ending preferential treatment for Hong Kong in response to a new security law brought in by China.
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In response to the 5G network ban, Chinese ambassador Liu Xiaoming questioned whether the UK can provide a "fair" business environment for foreign firms.
"Disappointing and wrong decision by the UK on Huawei," he tweeted.
"It has become questionable whether the UK can provide an open, fair and non-discriminatory business environment for companies from other countries."
Huawei's chief security officer in the US, Andy Purdy, said the move was "very bad news for Huawei" but that the UK would suffer an "even greater negative impact" both financially and on the "equality of service between rural Britain and urban Britain".
He told BBC Radio 4's Today programme that Huawei hopes the UK government will reconsider its decision, and offered "additional information" to give ministers "the level of confidence that has been shaken" by the US government's sanctions.