Private intelligence analysis firm Strategic Forecasting Inc., which was attacked by online hackers at the weekend, said in a letter to free subscribers that it has decided to delay the launching of its website by about a week.

The website of Strategic Forecasting, also known as Stratfor, has been offline for several days following the hacking attack.

As part of our ongoing investigation, we have also decided to delay the launching of our website until a thorough review and adjustment by outside experts can be completed, Stratfor said in an email.

The firm had earlier disclosed that its website had been hacked and that some information about its corporate subscribers had been made public.

The hacking group known as Antisec has claimed responsibility for the attack and promised to cause mayhem by releasing stolen documents.

An unauthorized party illegally obtained and disclosed personally identifiable information and related credit card data of some of our paying subscribers, Stratfor said in the email.

Stratfor also said in its letter that it would offer identity theft protection and monitoring services to affected subscribers.

(Reporting by Sakthi Prasad in Bangalore; Editing by Ed Lane)