Hackers attacked several top Czech news websites on Monday, overloading them with hundreds of thousands of requests per second to make them inaccessible, publishers said.
"News servers have been facing a massive DDos (Distributed Denial of Service) attack since 8:30 am (0730 GMT)," iDNES.cz, the website of the top-selling Czech broadsheet DNES, said on its Facebook profile.
"Servers are flooded with hundreds of thousands of nonsensical requests and their response speed decreases," it added.
The attacks follow last week's wave of cyber attacks on media and other sites worldwide, including Apple, Microsoft and Facebook.
Monday's attack probably came from Czech hackers, said Lucie Tvaruzkova, editor-in-chief at IHNED.cz, the website of the business daily Hospodarske Noviny.
"In the past, DDoS attacks were led from abroad so it was enough to block the server from foreign users. This time it seems to come from the Czech Republic," she said on Facebook.
Both iDNES.cz and IHNED.cz were again working shortly after noon (1100 GMT), as was E15, the website of an eponymous business daily also attacked by hackers.