(CNN Business)Officials in Europe are yet again ratcheting up the pressure on Silicon Valley titans.

The European Union's top court ruled Tuesday that tech giants regulated by privacy officials primarily in one EU country can still face legal action by privacy officials based in another member country. The ruling opens the door to more litigation against Big Tech by country-level European data watchdogs.

Separately, the UK's antitrust regulator said Tuesday it is investigating Apple(AAPL) and Google(GOOGL)'s dominance in mobile operating systems, app stores and web browsers.

The announcements mark the latest governmental challenges to Big Tech across the Atlantic, where scrutiny by regulators and policymakers have added to US policymakers' own efforts to rein in large, dominant platforms.

More in category

Zoom Agrees To Settle A Privacy Lawsuit For $85 Million
August 01, 2021NPR
Zoom Agrees To Settle A Privacy Lawsuit For $85 Million
Italian sprinter takes gold in men's 100-meter dash
August 01, 2021CBS
Italian sprinter takes gold in men's 100-meter dash
Florida breaks single-day COVID-19 cases record
July 31, 2021CBS
Florida breaks single-day COVID-19 cases record
Biden officials say US is still better off than earlier in pandemic despite new steps to fight Delta variant
August 01, 2021CNN
Biden officials say US is still better off than earlier in pandemic despite new steps to fight Delta variant
Belarusian sprinter in Tokyo: 'I am afraid that I might be jailed in Belarus'
August 01, 2021CNN
Belarusian sprinter in Tokyo: 'I am afraid that I might be jailed in Belarus'
The 2019 Golden Ray shipwreck off Georgia's Jekyll Island is leaking oil
August 01, 2021CNN
The 2019 Golden Ray shipwreck off Georgia's Jekyll Island is leaking oil
Enten shares 'mind boggling' data about the unvaccinated
August 01, 2021CNN
Enten shares 'mind boggling' data about the unvaccinated
Wildfire-weary West faces thunderstorms, potential flash floods
August 01, 2021USA Today
Wildfire-weary West faces thunderstorms, potential flash floods
Miami Beach Mayor Blames DeSantis After Florida Sets COVID-19 Case Record
August 01, 2021Newsweek
Miami Beach Mayor Blames DeSantis After Florida Sets COVID-19 Case Record
China Tests Millions, Issues New Travel Guidances as Outbreak Spreads
August 01, 2021Newsweek
China Tests Millions, Issues New Travel Guidances as Outbreak Spreads
'Rain City' Faces 47-Day Dry Streak as Seattle Hits 4th-Longest Drought
August 01, 2021Newsweek
'Rain City' Faces 47-Day Dry Streak as Seattle Hits 4th-Longest Drought
BLK Girls Green House creates plant sanctuary for community
August 01, 2021KRON4
BLK Girls Green House creates plant sanctuary for community
Mask mandates by states: As COVID cases spike, see what the rules are where you live
August 01, 2021USA Today
Mask mandates by states: As COVID cases spike, see what the rules are where you live
'Jungle Cruise' sets sail with a $90 million debut in theaters and streaming
August 01, 2021CNN
'Jungle Cruise' sets sail with a $90 million debut in theaters and streaming
McCarthy jokes 'it will be hard not to hit' Pelosi with gavel if he becomes House speaker
August 01, 2021CNN
McCarthy jokes 'it will be hard not to hit' Pelosi with gavel if he becomes House speaker
Dr. Fauci Says More ‘Pain and Suffering’ Ahead as COVID-19 Cases Rise
August 01, 2021TIME Magazine
Dr. Fauci Says More ‘Pain and Suffering’ Ahead as COVID-19 Cases Rise
From police traffic stops to qualified immunity for officers, 5 ways to reform policing
August 01, 2021USA Today
From police traffic stops to qualified immunity for officers, 5 ways to reform policing
Collins criticizes Jan. 6 panel as 'partisan,' Kinzinger says Trump may not need to testify
August 01, 2021USA Today
Collins criticizes Jan. 6 panel as 'partisan,' Kinzinger says Trump may not need to testify
Here's a full list of gold medal winners from Sunday
August 01, 2021CNN
Here's a full list of gold medal winners from Sunday
Lollapalooza Drops DaBaby From Lineup Following Homophobic Remarks
August 01, 2021Newsweek
Lollapalooza Drops DaBaby From Lineup Following Homophobic Remarks
Paul Gosar's Family Tears Into Him in Op-Ed—'Have You No Sense of Decency?'
August 01, 2021Newsweek
Paul Gosar's Family Tears Into Him in Op-Ed—'Have You No Sense of Decency?'