National Investigation Agency (NIA) has shut its website following reports of security breach though it claimed it was tightening safety mechanism following hacking of government websites.

The NIA, formed in the aftermath of 26/11 Mumbai attacks in 2008, had created its website with the help of National Informatics Centre (NIC). However, the address "nia.gov.in" on Tuesday read that the site is under construction.

Sources in NIC, which mans all the government websites, said there was an urgent message from the NIA for shutting its website after certain documents were placed on it which could be termed as a security breach.

Senior NIA officials, however, said the website was taken off from the cyber space in order to further tighten the security so that it becomes impregnable for hackers.

"Taking a cue from the hacking incident of CBI and recent attempt to enter into the NSG internal mail, we decided to revisit out security mechanism of the website," a senior NIA officials.

In December last year, the home page of the CBI website had a message from the 'Pakistani Cyber Army' warning the Indian Cyber Army not to attack their websites.

The hackers have been able to attack some other vital websites besides 270 other non-governmental website which include some media houses.