KUALA LUMPUR (Feb 5): Police will investigate a bomb threat posted on Facebook against Prime Minister Datuk Seri Najib Razak, Deputy Inspector-General of Police Datuk Seri Noor Rashid Ibrahim says.

He also warned social media users to be careful with their posts.

"This is a threat. We will take appropriate action, we will investigate.

"If we can identify (him) we will take action, arrest and charge him," he told reporters today when asked about a post by a Facebook user threatening to bomb the prime minister's residence tomorrow over "hardship" caused to Malaysians.

News site Malaysiakini reported on the post, which was said to have received a few "likes".

It read, "I will shake Kuala Lumpur and the Malaysian prime minister's residence with a bomb explosion this Saturday because Najib is causing hardship to the people."

Malaysiakini also reported that Gerakan Merah (Red Movement) leader Mohd Ali Baharom, also known Ali Tinju, had lodged a police report on the Facebook post, which had since been deleted and the account disabled.

Noor Rashid said people had to know the "limit" in what they posted on social media.