Speculation last night that WikiLeaks may reveal clandestine US support for terrorism had US embassies across the globe scrambling to limit damage ahead of the latest threatened release of US government documents by the whistleblowing website.

WikiLeaks is planning to make available up to 400,000 sensitive cables from the past five years that include talks with politicians, government officials and journalists, as well as evaluations by US diplomats about their host countries.

According to the London-based Arabic-language newspaper al-Hayat, several documents show that the US had in turn been providing assistance to Turkey's Kurdish separatist movement, the PKK.

Advertisement: Story continues below

Founded in the 1970s, the PKK is listed as a terrorist organisation in Turkey, the US, the European Union and Australia.

A report in Israel's Jerusalem Post said the US military documents refer to the PKK as ''warriors for freedom and Turkish citizens'' and say that the US had set free arrested PKK members in Iraq.

The documents also point out that US forces in Iraq have given weapons to the PKK and ignored the organisation's operations inside Turkey.

One of the documents to be released is also believed to charge Turkey with providing indirect assistance to the terrorist group al-Qaeda by failing to properly control the movement of people across its shared border with Iraq.

The document alleges that Iraqi citizens living in Turkey with ties to al-Qaeda were able to move freely in and out of Iraq and supply al-Qaeda with bomb-making materials and ammunition.

Another Israeli newspaper, Haaretz, reported that Israeli officials were apprehensive over the WikiLeaks material. The newspaper reported that the US embassy in Tel Aviv had informed Israel's Foreign Ministry of the imminent disclosures, some of which might deal with Israel-US relations.

According to Haaretz, if cables from the US embassy in Tel Aviv were released, it could be embarrassing because they deal with relations between Israel and the US, or because they involve correspondence between US diplomats that do not always reflect the official position of Washington.

A senior Israeli official familiar with the contents of the message quoted by Haaretz, who asked to remain anonymous, said the material includes diplomatic cables sent to Washington from US embassies throughout the world.

According to the official, the US embassy said the documents were not highly classified.

''The Americans said they view the leak very seriously. They don't know when they will be released on the internet and what exactly they say, but they didn't want us to read about it in the newspapers,'' the Israeli official said.

Kurt Hoyer, spokesman for the US embassy in Tel Aviv, neither confirmed nor denied that the embassy had conveyed a message relating to the matter to the Israeli Prime Minister's Bureau and the Foreign Ministry.

In two previous releases of secret US government documents by WikiLeaks, in July and October, documents were provided in advance to The New York Times, The Guardian newspaper in London and the German magazine Der Spiegel on condition that they publish their stories simultaneously.

The first leak contained thousands of military field reports on the war in Afghanistan; the second was a similar but larger file on the Iraq war.

According to Reuters, the same three media organisations had again already been given access to the documents by WikiLeaks founder Julian Assange. It is unclear when the information will be made public.

Last week a Swedish appeals court upheld a court order to detain Assange, 39, for questioning over allegations of rape and sexual molestation.

Assange, an Australian citizen, denies the accusations.