Sony says its PlayStation Network is back online after three days of disruptions that began on Christmas.

But heavy traffic might continue to cause problems for customers seeking to play their favorite games, the company said Sunday.

A group of hackers called Lizard Squad — or someone claiming to speak for it — took credit for the disruptions. In a blog post Saturday night saying service had been restored, Sony Vice President Catherine Jensen added that “PlayStation Network and some other gaming services were attacked over the holidays with artificially high levels of traffic to disrupt connectivity and online gameplay.”

Microsoft's Xbox Live service, which also went down Thursday, was back online Friday, although the company reported continuing problems.

So far, there's no evidence to link these episodes with last month's attack on Sony Pictures Entertainment. The FBI has blamed that attack on North Korea, which was furious about Sony's “The Interview.”

BEIJING — Connections to Google’s popular e-mail service have been blocked in China amid efforts by the government to limit access to the company’s services.Records from Google’s Transparency Report show online traffic from China to Gmail dropped to nearly zero Saturday, although there was a tiny pickup today.Calls to the regulator, the China Internet Information Office, were unanswered today. Foreign Ministry spokesman Hua Chunying did not confirm the block but said China welcomes foreign investors who legally conduct business in China.Google closed its mainland China search engine in 2009, saying it would no longer cooperate with the country’s censors. That followed hacking attacks traced to China aimed at stealing the company’s operating code and breaking into e-mail accounts.