WASHINGTON - Hackers broke into the US Senate's public website for the second time in a week but were prevented from getting any sensitive data, a security spokeswoman said on Wednesday.

The US Senate's website had also been hacked over the weekend, leading to a review of all its websites, in the latest embarrassing breach of security to hit a major US-based institution.

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This attack was similar in that hackers broke into the public site and downloaded information, said Martina Bradford, the deputy Senate sergeant at arms. The Sergeant at Arms Office provides security for the Senate.

"They're getting nothing but the attacks continue," said Bradford. "We've been able to stay ahead of the hackers and keep them out of the main Senate network."

The loosely organized hacker group Lulz Security broke into a public portion of the Senate website over the weekend and announced the hack in a tweet on Monday. Lulz, whose name derives from Internet slang for "laugh out loud," tweeted on Wednesday but has not mentioned hacking the Senate website.

Recent weeks have seen a long string of embarrassing hacks. The International Monetary Fund has been hit, as have Lockheed Martin Corp, Citigroup Inc, Google and Michaels Stores.

Lulz has claimed hacks into websites owned by Sony Corp as well as US Public Broadcasting Service and Fox.com. Fox is a unit of News Corp.