US diplomats have been barred from participating in The ALS Ice Bucket Challenge charity drive, according to an official statement sent to all US diplomat missions, AP News reports.

The fundraising dare has taken the internet by storm, with celebrities including Bill Gates, Justin Timberlake, Charlie Sheen, Lady Gaga and George W. Bush recording their ice bucket videos, in a bid to raise funds and spread awareness of ALS (amyotrophic lateral sclerosis).

In an unclassified cable (see below), obtained by the Associated Press on Thursday (21 August), lawyers at the US State department have said that participating in the challenge is against the federal ethics rules, adding that public office cannot be used for private gains.

Notes from the cable read: "There are firmly established rules preventing the use of public office, such as our ambassadors, for private gain, no matter how worthy a cause.

"Thus, high-ranking State Department officials are unfortunately unable to participate in the ice bucket challenge. We since wish the ALS Association continued success in its ice bucket campaign, and in its fight against Lou Gehrig's disease."

The statement added that health awareness is one of the State Department's top priorities, citing the US funding for global HIV/Aids, tuberculosis, malaria and the recent initiatives to manage the Ebola virus outbreak.

It also complimented the ALS Association for securing over £24 million ($40 million) from the Ice Bucket Challenge.

US Ambassador to Israel, Daniel B. Shapiro, was the only high-ranking US diplomat to have participated in the challenge before the cable was circulated, reported AP News.