Israeli government websites were up and running again Monday, after what the government described as a "server glitch" at a server farm took several of them offline.

Websites including those of the Mossad intelligence service, Israel Defense Forces (IDF), and the Israeli Security Agency known as Shabak or Shin Bet were either inaccessible or under maintenance late Sunday, raising the suspicion that the outage was the handiwork of the hacker group Anonymous.

On Friday, Anonymous threatened to attack Israel if it continued its blockade of the Gaza Strip. However, Anonymous hasn't claimed credit for an attack.

The Israeli government has meanwhile said repeatedly that its websites have not been hacked.

"All of the Israeli government websites which were down yesterday are now back up. Once again - it wasn't a cyber attack but a server glitch," said Ofir Gendelman, a spokesman in the Israel Prime Minister's Office, in a Twitter message on Monday.

The problem was in the government's server farm, called "Tehila", which is operated by the Ministry of Finance, Gendelman said in an email.

"There was a glitch in one of the servers that carry websites of a few ministries and government agencies, including the IDF spokesperson's website," he wrote.

Gendelman did not provide the details of the server glitch, though according to Israeli newspaper reports there was a malfunction in a storage component. The websites of the Prime Minister's office and Ministry of Foreign Affairs did not crash, which is another proof that it wasn't a cyber attack, he said.

John Ribeiro covers outsourcing and general technology breaking news from India for The IDG News Service. Follow John on Twitter at @Johnribeiro. John's e-mail address is john_ribeiro@idg.com