Describing Dr Mahathir Mohamad's criticism as negative, the special affairs department (Jasa) has vowed to launch an offensive against the former premier on the social media.

"We consider it very negative. Hence, Jasa would face the situation and not be defensive but offensive (through the social media)," said the department's director-general Puad Zarkashi.

"Why did Mahathir raise the Sirul (Azhar Umar) issue when it has been decided by the court?

"It is unwise for Mahathir to raise this issue as if he has new evidence," the former Umno lawmaker and deputy minister was quoted as saying in an Astro Awani news report.

Puah said Jasa's "attack" is aimed at correcting public perception and to weaken those who smear the government.

He explained that if the issue is not tackled properly, it would affect the position of the government.

"There are governments who have lost an election as a result of the social media.

"This happened in other countries and we certainly do not want this medium (social media) to be used to slander the government," Puad added.

However, a Bernama report on the same function did not mention Mahathir but rather highlighted the Jasa chief criticising the opposition for not using the proper channel to seek answers.

Mahathir, in his blog posting yesterday, called for an investigation to determine who had issued the order to kill Altantuya Shaariibuu .

The former premier said it would be wrong for Sirul, a former police commando, to be hanged for following instructions.

Mahathir also warned that BN and Umno would lose the next general election if Najib remained at the helm.