Jesse Rodriguez of NBC reported the cancellation of the announcement, which was to go forward on Tuesday from the balcony of the Ecuadorian Embassy in London.
Assange has sought sanctuary from the United States for five years and is living at the embassy. This was due to a sex scandal that happened in Sweden in 2010 when he had sex with two women who later filed charges that they were forced against their will.
The so-called 'security concerns' have not been elucidated and WikiLeaks has not announced when it will make its "announcement."
When Assange appeared on Fox News last month, he said that WikiLeaks has damaging information on Hillary and may soon release "teasers." But so far, this has not happened.
Although #NeverHillary people hope like crazy Assange has material to destroy Clinton's chances in the election, there is no evidence that this information even exists.
But if anybody has information that could destroy her presidential hopes, it would be the five people the FBI granted immunity to, and the guy who did the granting--James Comey.