The NSA has been collecting details about the online sexual activity of prominent Islamist radicals in order to undermine them, according to a new Snowden document published by the Huffington Post.

The American surveillance agency targeted six unnamed "radicalisers", none of whom is alleged to have been involved in terror plots.

One document argues that if the vulnerabilities they are accused of were to be exposed, this could lead to their devotion to the jihadist cause being brought into question, with a corresponding loss of authority.

As an example of vulnerabilities, it lists: "Viewing sexually explicit material online or using sexually persuasive language when communicating with inexperienced young girls."

The names of the six targeted individuals have been redacted. One is listed as having been imprisoned for inciting hatred against non-Muslims. Under vulnerabilities, the unnamed individual is listed as being involved in "online promiscuity" as well as possibly misdirecting donations.

Shawn Turner, press spokesman for the US director of national intelligence, in an email to the Huffington Post, said it was not surprising the US government "uses all of the lawful tools at our disposal to impede the efforts of valid terrorist targets who seek to harm the nation and radicalise others to violence".

The article was written by the former Guardian journalist Glenn Greenwald, who met the NSA whistleblower Edward Snowden in Hong Kong in May and was given a large cache of leaked documents.

One of the documents says the aim is to look at "six prominent, globally resonating foreign radicalisers", the audiences they reach and potential vulnerabilities.

It says: "Communications profiles of these English-language radicalisers reveal that very few of contacts noted were associated with terrorism, suggesting that the target audience includes individuals who do not yet hold extremist views but who are susceptible to the extremist message."

Vulnerabilities identified include: "publishes articles without checking facts"; "deceitful use of funds"; "charges exorbitant speaking fees"; "attracted to fame"; and "glamorous lifestyle".

One of the six is described as a "US person", meaning a citizen or permanent resident, but the others are not identified other than to say they are living outside the US. A document said a significant proportion of their audience was in Pakistan.