With four allegedly “malicious” attacks done on the Australia Census 2016 website, the survey has remained incomplete, as many people could not fill in their information online.

Prime Minister Malcolm Turnbull has responded to the suspected attacks, saying that he would see to it that the Census data tampering was not forgiven. The attempt has disturbed the complete system of the online survey, which the Australian Bureau of Statistics introduced for the first time.

While taking to 2GB on Thursday, Turnbull also confirmed the “serious failure” of the Census website in keeping the data safe, though no signs of leakage of data have yet been obtained. It has been 36 hours now since the website went out of action. ABS shut the website down on Tuesday, igniting a flame of suspicion among Australians of their information being leaked to malicious people or organizations.

After three minor attacks, a fourth attempt of violating online data through “denial of service” was made, which prompted the ABS to close the website so that the data are not tampered with or obtained by malicious groups. Turnbull did not specify what steps he would take as far as sacking people associated with the carelessness in maintaining the website is concerned but he indicated “very serious consequences”.

The prime minister expressed his disappointment over the action and said that the “denial of service” attack was a very common scenario for which the regulators of the website should have been prepared beforehand. The Census website with confidential information must have been provided with greater security. He blamed ABS and IBM, the contractors, for the lack of security provision to the website, which led to the event.

“My calm demeanor on your radio program is disguising the fact … that I too am very angry about this. I am bitterly disappointed about this,” News.com.au quoted him as saying.

Meanwhile, the ABS said that the ones who tried to tamper with the Census 2016 data belonged to overseas hacking groups and their only motive was to sabotage the national survey.