The website has collated a variety of records including cables, intelligence reports and congressional correspondence and is releasing them in a searchable form.
Assange has carried out much of the work from his refuge in Ecuador’s embassy in London and told the domestic Press Association that the records highlighted the “vast range and scope” of US influence around the world.
Assange has been holed up in the tiny diplomatic mission for nine months as he seeks to avoid extradition to Sweden over allegations of rape and sexual assault, which he denies.
WikiLeaks sent shockwaves around the diplomatic world in 2010 when it released a set of more than 250 000 leaked US cables.
The new records, dating from the beginning of 1973 to the end of 1976, have not been leaked and are available to view at the US national archives. They include many communications which were sent by – or to – then-secretary of state Henry Kissinger.
Many of the documents, which WikiLeaks has called the Public Library of US Diplomacy (PlusD), are marked NODIS (no distribution) or Eyes Only, while others were originally marked as secret.
Assange fled to the Ecuadorian embassy in June after losing his battle in the British courts against extradition to Sweden.
Ecuador granted him asylum in August, but Britain has refused to allow him safe passage out of the country, sparking a diplomatic stalemate.
Assange founded the WikiLeaks website that enraged Washington by releasing cables and war logs relating to the wars in Iraq and Afghanistan in one of the biggest security breach in US history. – Sapa-AFP