The Trump administration has announced sweeping restrictions on two popular Chinese social media networks, TikTok and WeChat, a sharp escalation of its confrontation with China that is likely to be met with retaliation.

Two executive orders, released late on Thursday and taking effect in 45 days, cited national security concerns to bar any transactions with WeChat or TikTok by any person or involving any property subject to the jurisdiction of the US. The order essentially sets a 45-day deadline for an acquisition of TikTok, which is in talks to be acquired by Microsoft.

Tensions between the US and China have already escalated to levels not seen in decades over rifts in geopolitics, technology and trade. In recent months, Trump administration officials have challenged China on its crackdown in Hong Kong, its territorial claims in the South China Sea and its efforts to produce global tech champions.

The campaign has been provoked in part by China’s more assertive posture, but also President Trump’s desire to convince voters that he is tough on China as the election approaches.

Trump’s advisers have zeroed in on technology companies, which they say are beholden to the Chinese government through security laws. Many companies that do business across the Pacific have been left paralywed or begun to reconsider their partnerships, unsure of whether these tensions will spill into a new Cold War.

The restrictions announced Thursday would also represent a further balkanisation of the global Internet, as nations continue to cut off foreign technology companies from one another’s markets.

In the announcement, Trump accused WeChat, made by Tencent, and TikTok, made by ByteDance, of providing a channel for the Chinese Communist Party to obtain Americans’ proprietary information, keep tabs on Chinese citizens abroad and carry out disinformation campaigns to benefit China’s interest.

“The spread in the United States of mobile applications developed and owned by companies in the People’s Republic of China (China) continues to threaten the national security, foreign policy and economy of the United States,” the President wrote.

Much remains unclear about the scope of the ban, including precisely which transactions would be covered. But it appears to have even more severe consequences for WeChat than for TikTok, which could be rescued through its talks with an American suitor.

WeChat is used widely around the world, particularly by people of Chinese descent, to communicate with friends, read news and carry out business transactions, and such a ban could effectively cut off much informal communication between people in China and the US. Questions remain as to whether the order will affect businesses tied to Tencent, WeChat’s parent company, which is an investor in many popular American technology and gaming start-ups.

“We are reviewing the executive order to get a full understanding,” a Tencent representative said early Friday. The company’s shares fell almost 6 per cent in trading on Friday.

In a statement on Friday, TikTok said it was “shocked” by the order, which it said risked “undermining global businesses’ trust in the United States’ commitment to the rule of law”.