The ministers received on Sunday a circular sent by Cabinet Secretary K M Chandrashekhar on behalf of the Prime Minister.
The Cabinet Secretary stated in his missive that the prime minister ''desires'' that ministers should not remark on the internal security of the country and should not voice ''different opinions'' on the matter.
The Home Ministry is competent to react to such matters, it added.
The Prime Minister's direction comes after the April 6 massacre of 76 security personnel in the forests of Chhattisgarh, the largest Maoist attack in four decades.
It is learnt that the Prime Minister gave the direction for the circular after colleagues like Railway Minister Mamata Banerjee and Food Processing Minister Subodh Kant Sahay commented on the attack.