including some top secret material. the documents first appeared on online platforms, such as twitter, lichan and telegram, as well on the messaging platform discord. the leak reveals information about the deployment and state of ukrainian and russian forces ahead of a ukrainian spring offensive, and appear to outline us training and equipment being provided to ukraine ahead of that offensive. there are also suggestions that ukraine s air force may not be able to withstand more russian attack. may not be able to withstand more russian attacks. other leaked material included intelligence on other countries such as china, israel, and south korea. officials say they do not currently know the source of the leaks. the bbc s barbara plett usher has more. the pentagon says the us is still very much into the finding out phase. we are told this is a serious risk to us national security and a matter of top priority. a number of