As his brother, Johor Crown Prince Tunku Ismail Sultan Ibrahim, came under fire from a federal minister, younger brother Tunku Idris posted an eyebrow-raising image on Instagram.

The image was purportedly that of Johor's agreement to becoming part of the Federation of Tanah Melayu.

The Sunday posting - which was removed today without explanation - came after Tourism and Culture Minister Nazri Abdul Aziz warned Tunku Ismail not to meddle in politics or risk being "whacked".

The image posted by Tunku Idris stated that the late Sultan Abu Bakar inked the 'Perjanjian Setia' in 1885 between the Johor government and British government.

"At the time Johor was known as the independent and sovereign state of Johor.

"In 1946, the Johor government agreed to sign the Perjanjian Persekutuan with the Persekutuan Tanah Melayu, by imposing several conditions, including Islam as the official religion of the state, the land in Johor being the absolute right of the Johor government and cannot be disturbed without the agreement of the Johor government, the Askar Timbalan Setia Negeri cannot be disbanded, as well as the power of the Johor government being in the hands of the sultan.

"If any of the conditions are violated, Johor will be out of Malaysia [sic]."

There was no title or caption with regard to the 28-year-old prince's posting, but other Instagram users touched on the issue of secession.

Some of the comments ranged from agreeing to Johor quitting the Federation, while others urged the young prince to keep calm.

Yesterday, some 2,000 Johoreans staged a rally outside the Istana Bukit Serene in support of the royal family and called for Nazri’s resignation.

The minister, however, has refused to back down .