Federal minister Ismail Sabri Yaakob said he does not know what was in Idris Haron's head when the latter claimed the United States was trying to topple Prime Minister Najib Abdul Razak and the Malays.

Idris, who is Malacca chief minister, had claimed last Sunday that the US was doing this through the Department of Justice (DOJ) lawsuits related to 1MDB.

When asked to comment on the matter, Ismail Sabri today refused to share his views on the alleged conspiracy, and directed journalists to ask Idris instead.

"That one, you have to ask him... as he was the one who made the statement, I cannot comment on what he said.

"I have no idea what is in his (Idris') head (and) why (he said so)," Ismail Sabri told a press conference in Kuala Lumpur today.

The rural and regional development minister had earlier signed a memorandum of understanding between Rubber Industry Smallholders Development Authority and Celcom-Axiata.

On Sunday, Idris alleged that after having killed Iraqis, the US is now coming after the Malays, and that the DOJ legal action is part of the conspiracy to remove Najib.

Idris also questioned the DOJ's credibility, and cited the 2003 US invasion of Iraq, which had been based on allegations that then Iraqi president Saddam Hussein had access to weapons of mass destruction.

Last month, the DOJ claimed that about US$3 billion in funds has been embezzled from 1MDB, filing civil suits to seize assets traced to the funds which it said was laundered through the US financial system.

In response, attorney-general Mohamad Apandi Ali claimed that there was no evidence of any embezzlement from investigations into the matter, though he said that police were still looking into the matter.