The legal adviser for the U.S. Department of State has sent a letter to WikiLeaks founder Julian Assange and his attorney, warning that his stated intention to publish more classified U.S. documents violates U.S. law.
The letter from Harold Koh, dated November 27, says it is in response to a letter sent by Assange to the U.S. Ambassador to Britain, stating Assange's decision to publish the documents on WikiLeaks.
State's letter warns that releasing the information could endanger the lives of U.S. service members, journalists and human rights activists. It also says the move could endanger ongoing cooperation between nations on issues such as terrorism, disease and nuclear proliferation.
On Friday, the State Department said Secretary Hillary Clinton has reached out to several countries about the WikiLeaks threat.
Department spokesman P.J. Crowley said on Twitter that Clinton reached out to the leaders of Germany, Saudi Arabia, the United Arab Emirates, Britain, France and Afghanistan.
A senior Israeli official quoted in Haaretz newspaper said his government was warned that some of the cables could include confidential reports from the U.S. embassy in Tel Aviv.
The London-based newspaper Al-Hayat is reporting the release will reveal U.S. support for the PKK, a Kurdish separatist group in Turkey listed by the State Department as a terrorist group.
It is not known when WikiLeaks will make the documents public. WikiLeaks announced on its Twitter page Monday that it is planning to publish almost 3 million secret documents.
The expected document dump would be seven times larger than the 400,000 documents the website released on the Iraq war.
WikiLeaks was founded by Assange, an Australian citizen and former computer hacker. The highly secretive Assange has been criticized by the Pentagon for his previous releases of confidential material. He is wanted in Sweden for questioning on a rape charge. He has denied the allegation.