WASHINGTON, March 25 (Reuters) - U.S. and British

officials on Monday filed charges, imposed sanctions, and

accused Beijing of a sweeping cyberespionage campaign that

allegedly hit millions of people including lawmakers, academics

and journalists, and companies including defense contractors.

Authorities on both sides of the Atlantic nicknamed the

hacking group Advanced Persistent Threat 31 or "APT31", calling

it an arm of China's Ministry of State Security. Officials

reeled off a laundry list of targets: White House staffers, U.S.

senators, British parliamentarians, and government officials

across the world who criticized of Beijing. Defense contractors,

dissidents and security companies were also hit, the officials

said.

The aim of the global hacking operation was to "repress

critics of the Chinese regime, compromise government

institutions, and steal trade secrets," Deputy U.S. Attorney

General Lisa Monaco said in a statement.

In an indictment unsealed on Monday against seven of the

alleged Chinese hackers, U.S. prosecutors in court said the

hacking resulted in the confirmed or potential compromise of

work accounts, personal emails, online storage and telephone

call records belonging to millions of Americans. Officials in

London accused APT31 of hacking British lawmakers critical of

China and said that a second group of Chinese spies was behind

the hack of Britain's electoral watchdog that separately

compromised the data of millions more people in the United

Kingdom.

Chinese diplomats in Britain and the U.S. dismissed the

allegations as unwarranted. The Chinese Embassy in London called

the charges "completely fabricated and malicious slanders."

Reuters was not immediately able to locate contact

information for the seven alleged hackers being charged by the

Department of Justice.

The announcements were made as both Britain and the U.S.

imposed sanctions on a firm they said was a Ministry of State

Security front company tied to the hacking activity.

The U.S. Treasury Department in a statement said the

sanctions were on Wuhan Xiaoruizhi Science and Technology, as

well as on two Chinese nationals.

"Today's announcement exposes China's continuous and brash

efforts to undermine our nation's cybersecurity and target

Americans and our innovation," FBI Director Christopher Wray

said in a statement.

Tensions over issues relating to cyberespionage have been

rising between Beijing and Washington, as Western intelligence

agencies have increasingly sounded the alarm on alleged Chinese

state-backed hacking activity.

China has also begun in recent years to call out alleged

Western hacking operations. For example, last year, the Ministry

of State of Security claimed that the U.S. National Security

Agency had repeatedly penetrated Chinese telecommunication giant

Huawei Technologies.

U.S. prosecutors listed numerous unnamed victims around the

globe who had been targeted, but several stand out in the

indictment.

In 2020, the Chinese hackers targeted staffers working for a

U.S. presidential campaign, prosecutors wrote. The disclosure

matches public reporting at the time by Google that Chinese

hackers sent malicious emails to the campaign of current

President Joe Biden, but no compromise had been detected.

Another alleged mission involved the hacking of an American

firm known for public opinion research in 2018, the same year of

a U.S. midterm election.

"Politicians, parties, and elections organizations are rich

sources of intelligence that offer collectors everything from

rare geopolitical insights to enormous troves of data, said John

Hultquist, chief analyst for U.S. cybersecurity intelligence

firm Mandiant, a division of Google owner Alphabet.

"As we've seen in previous election cycles, actors like

APT31 turn to political organizations to find the geopolitical

intelligence that they're tasked with collecting," Hultquist

said.

(Reporting by James Pearson, Christopher Bing and Raphael

Satter. Additional reporting by Daphne Psaledakis. Writing by

Raphael Satter and Christopher Bing. Editing by David Gregorio

and Marguerita Choy.)