Hackers thought to be part of the Anonymous organization attacked and took down the web sites of Mexico's interior department and Senate, officials in both government bodies said.
Friday's action, carried out in protest against an anti-piracy bill being promoted in Mexico, was widely noted on social networks like Twitter and was one of the subjects with the most followers (#OpDoring; #LeyDoring).
After the hacking attack, the Mexican Senate issued a brief communique acknowledging that its Internet page was taken down shortly after noontime "after being hit with four cyberattacks aimed at blocking the service" in less than an hour.
"The Web site is being monitored with specialized resources and will be back up as soon as the flood of attacks diminishes and will be completely accessible to citizens' visits," the message said.
For its part, officials at the interior department, which has a hand in everything from law enforcement to disaster relief and running elections, told Efe that its Web site (www.segob.gob.mx) had been inaccessible for several hours.
Later Saturday the interior department Web site was still down, while that of the Senate was again functioning normally.
During a visit to the southeastern city of Merida, Government Secretary Alejandro Poiré said that the government is "working systematically to prevent these attacks and assure the necessary backup for its databases."
"We must keep in mind that if crimes have been committed, they will be investigated to bring the perpetrators to justice," he said.
Sen. Federico Doring of Mexico's ruling conservative National Action Party is promoting a bill that aims to modify the laws on royalties and intellectual property.
The bill, which tries to prevent illegal downloading and impose fines for repeated infractions of this kind, has been slammed by the Mexican Internet Association, or Amipci, which considers it an attempt to "criminalize the Internet."
On Jan. 18, the day when there was an Internet "blackout" in the United States in protest against the anti-piracy bill known as the Online Piracy Act, some Web sites denounced the Mexican bill, known as the Doring Law.
In Mexico the crimes committed most frequently on the Internet are identity theft, fraud, extortion, child pornography and piracy.
This country has some 40 million cybernauts, according to Amipci estimates.