The Umno supreme council had been warned of possible unrest in Memali, said former deputy prime minister Musa Hitam.

However, Musa said they paid little attention to the developments, which would end with the deaths of 14 civilians and four police officers in 1985.

"As a member of the council myself and deputy president of the party, I believed it was my duty to brief members on what was going on in Memali as a result of this ustaz (Ibrahim Mahmood @ Ibrahim Libya ).

"Regrettably, however, the council gave the matter scant attention.

"Only (then Terengganu menteri besar) Wan Mokhtar (Ahmad) showed any interest... I remember he warned council members that (Ibrahim's) gatherings, if not stopped, could spark political unrest," Musa wrote in his book 'Frankly Speaking'.

He was referring to the gatherings of large crowd to hear Ibrahim, a religious preacher, speak.

Musa, who was also home minister at the time, said information about the gatherings had been obtained from police, and from Wan Mokhtar, who was also then Umno head of religious affairs.

The incident ended bloodily, when Ibrahim's supporters and the police trying to arrest the preacher clashed in November 1985.

Musa was believed to be acting prime minister at the time, and was held responsible for the massacre.

However. he broke his silence in 2014 to reveal that then premier Dr Mahathir Mohamad was still in Malaysia when the incident took place.

In his book, Musa related how he had recommended that Mahathir postpone his trip to China to deal with the incident.

Mahathir said he would think about, but Musa claims he called shortly afterwards to tell his deputy: "I'm going (to China). You take care of this."

The former premier has admitted to being in the country at the time of the massacre, but insisted that it happened under Musa's watch as home minister.