SEOUL - South Korea's top court on Thursday said Alphabet Inc's Google should disclose whether the technology giant had shared local user information with third parties, news agency Yonhap reported, sending the case back to a lower court.

The Supreme Court's decision came after a group of four plaintiffs filed a lawsuit against Google and its South Korean unit in 2014 to force the company to disclose the handling of local users' privacy data.

The group alleged that the tech company had shared private user information through PRISM, a U.S. National Security Agency surveillance programme.

"We will review the Supreme Court's full written decision carefully," a Google spokesperson said.

On the same day, the Supreme Court also upheld a previous ruling ordering Qualcomm to pay a fine of about 1 trillion won ($761.68 million) for abusing its dominant market position, the Korea Fair Trade Commission (KFTC) said.

Qualcomm did not respond immediately to a request for comment.

The Supreme Court's decisions on both cases are in line with South Korea's recent tendency to take a tough stance on regulatory matters concerning foreign technology giants.

On Wednesday, South Korea's anti-trust regulator fined Google 42.1 billion won ($31.88 million) for blocking the release of mobile video games on a competitor's platform.

The KFTC said the move against the U.S. technology giant was part of efforts by the government to ensure fair markets.

  - Reuters