Final answer:
The police posted a proclamation asking all citizens to desist from looting. It is a formal announcement addressing the public to stop specific actions.
Step-by-step explanation:
The police posted a proclamation asking all citizens to desist from looting. A proclamation is a public or official announcement that deals with a matter of great importance. In the context provided, it refers to a notice issued by the authorities like the police to address certain behaviors or actions of the public -- in this case, to stop looting. For example, historical documents show that proclamations have been used to mobilize the public or to offer rewards, similar to the one mentioned in the LibreTexts reference which offered a reward for the return of a young lady. In this context, the word asking is a gerund participle used as the head of a noun phrase functioning as the object of the verb posted. It represents an action of making a request or a call for a specific action from the citizens.