China has threatened to retaliate against US sanctions seen as an attempt to restrict international trade by the Chinese technology giant Huawei.

Foreign Ministry spokesman Lu Kang said Beijing opposed countries imposing unilateral sanctions on Chinese companies and would take action.

The order does not name any company, but is believed to target Huawei.

Huawei denies its products pose a security threat and says it is ready to engage with the US.

Beijing accused President Trump of engaging in industrial sabotage by using state security as "as a pretext for suppressing foreign business".

"We urge the US to stop this practice and instead create better conditions for business co-operation," Lu said. He did not give any details over how China planned to retaliate.

The confrontation over Huawei comes amid a broader trade war between the US and China, with both sides imposing aggressive tariffs on imports.

"China is always open for talks but it would fight to the end should a 'trade war' break out," he wrote.

What did the US sanctions order say?

According to a White House statement, Trump's order aims to "protect America from foreign adversaries who are actively and increasingly creating and exploiting vulnerabilities in information and communications technology infrastructure and services".

It gives the secretary of commerce the power to "prohibit transactions posing an unacceptable risk to the national security", the statement adds.

The move was instantly welcomed by Federal Communications Commission Chairman Ajit Pai, who called it "a significant step toward securing America's networks".

The US had already restricted federal agencies from using Huawei products and has encouraged allies to shun them, while Australia and New Zealand have both blocked the use of Huawei gear in 5G networks.

In April 2018 another Chinese tech company, ZTE, was barred from buying US parts after it was placed on the same "entity list". It resumed business after reaching a deal with the US in July.