China on Saturday slammed the United States for imposing "barbarous" sanctions against Hong Kong officials, capping a dramatic week of deteriorating relations between the world's two biggest economies.

In the toughest U.S. action on Hong Kong since China imposed a sweeping new security law on the territory, Washington on Friday sanctioned a group of Chinese and Hong Kong officials — including the city's leader Carrie Lam.

The move came after President Donald Trump's administration forced Chinese internet giants TikTok and WeChat to end all operations in the U.S., in a twin diplomatic-commercial offensive set to grow ahead of the U.S. presidential election in November.

China on Saturday criticized the sanctions as "barbarous and rude".

"The ill intentions of U.S. politicians to support people who are anti-China and messing up Hong Kong have been clearly revealed," Beijing's Liaison Office in Hong Kong said in a statement.

The Treasury Department announced it was freezing the U.S. assets of Chief Executive Carrie Lam and ten other senior officials, including Luo Huining — the head of the Liaison Office.

It accused the sanctioned individuals of being "directly responsible for implementing Beijing's policies" in Hong Kong.

The move criminalizes any U.S. financial transactions with the sanctioned officials.

In a short statement, Luo said he welcomed the blacklisting.

"I have done what I should do for the country and for Hong Kong," he said.

"I don't have a dime's worth in foreign assets."

The Hong Kong government described the sanctions as "shameless and despicable".

A city government spokesman said in a statement that Washington was using "Hong Kong as a pawn in its ploy to create troubles in China-US relationship".

Participants hold up their cellphone's flash lights as they take part in a rally in Central district on June 9, 2020 in Hong Kong, China. Photo: AFP

Tensions spike ahead of election

Beijing's security law was imposed in late June, following last year's huge protests in Hong Kong, sending a political chill through the semi-autonomous city.

Since then, authorities have postponed elections, citing the coronavirus pandemic, issued arrest warrants for six exiled activists and launched a crackdown on other activists.

U.S. Secretary of State Mike Pompeo said the security law violated promises made by China ahead of Hong Kong's 1997 handover that the city could keep key freedoms and autonomy for 50 years.

"Today's actions send a clear message that the Hong Kong authorities' actions are unacceptable," Pompeo said in a statement.

The U.S. measures come three months ahead of the November election in which Trump, who is behind his rival Joe Biden, is campaigning hard on an increasingly strident anti-Beijing message.

As public disapproval has grown for his handling of the pandemic, Trump has pivoted from his previous focus on striking a trade deal with China to blaming the country for the coronavirus crisis.

U.S. Secretary of State Mike Pompeo speaks at a press briefing at the State Department in Washington, DC, on April 22, 2020. Photo: AFP

Tik Tok, WeChat bans

On Thursday, Trump made good on previous threats against WeChat and TikTok — two Chinese-owned apps with major audiences that U.S. officials say pose a national security threat.

In an executive order, Trump gave Americans 45 days to stop doing business with the platforms, effectively setting a deadline for a potential, under-pressure sale of TikTok to Microsoft.

The move also threw into doubt the American operations of WeChat's parent firm, Tencent, a powerful player in the video game industry and one of the world's richest companies.

China condemned the move as "arbitrary political manipulation".

The new restrictions sent Tencent shares tanking as much as ten percent at one point in Hong Kong trade on Friday, wiping almost US$50 billion off its market capitalization.

Trump's order claimed TikTok could be used by China to track the locations of federal employees, build dossiers on people for blackmail and conduct corporate espionage.

TikTok has repeatedly denied sharing data with Beijing.

WeChat is a messaging, social media and electronic payment platform and is reported to have more than a billion users, with many preferring it to email.

The latest U.S. actions follow a protracted battle over Huawei, the Chinese network and smartphone giant accused by the Trump administration of being a tool for espionage.

In this photo illustration, the social media application logo, TikTok is displayed on the screen of an iPhone on an American flag background on August 3, 2020 in Arlington, Virginia. Photo: AFP