Israeli military and intelligence operatives are active in Kurdish areas of Iran, Syria and Iraq, providing training for commando units and running covert operations that could further destabilise the entire region, according to a report in the New Yorker magazine.

The article was written by Seymour Hersh, the Pulitzer Prize-winning reporter who exposed the abuse scandal in Abu Ghraib. It is sourced primarily to unnamed former and current intelligence officials in Israel, the United States and Turkey.

Israel's aims, according to Hersh, are to build up the Kurdish military strength in order to offset the strength of the Shia militias and to create a base in Iran from which they can spy on Iran's suspected nuclear-making facilities.

"Israel has always supported the Kurds in a Machiavellian way - a balance against Saddam," one former Israeli intelligence officer told the New Yorker. "It's Realpolitik. By aligning with the Kurds Israel gains eyes and ears in Iran, Iraq and Syria. The critical question is 'What will the behaviour of Iran be if there is an independent Kurdistan with close ties to Israel? Iran does not want an Israeli land-based aircraft carrier on its border."

By supporting Kurdish separatists, Israel also risks alienating its Turkish ally and undermining attempts to create a stable Iraq. "If you end up with a divided Iraq it will bring more blood, tears and pain to the Middle East and you will be blamed," a senior Turkish official told Mr Hersh.

Intel Brief, an intelligence newsletter produced by former CIA chiefs, noted early this month that the Israeli actions are placing increasing stress on their relationship with Turkey, which was already strained over the war. "The Turks are increasingly concerned by the expanding Israeli presence in Kurdistan and alleged encouragement of Kurdish ambitions to create an independent state."

According to Mr Hersh, Israel decided to step up its role in Kurdistan last summer after it was clear that the United States incursion into Iraq was failing, principally because it feared the chaos would strengthen Iran. The Israelis are particularly concerned that Iran may be developing a nuclear capability.

Iran said on Saturday it would reconsider its suspension of some uranium enrichment activities after the International Atomic Energy Agency issued a resolution deploring Iran's limited cooperation with the agency.

In the autumn the former Israeli prime minister Ehud Barak told the US vice president, Dick Cheney, that America had lost in Iraq. Israel "had learned that there's no way to win an occupation," he told Mr Cheney, and the only issue was "choosing the size of your humiliation".

From July last year, argues Mr Hersh, the Israeli government started what one former Israeli intelligence official called "Plan B" in order to protect itself from the fallout of the chaos prompted by America's failure ahead of June 30. If the June 30 transfer of sovereignty does not go well, "there is no fallback, nothing," a former National Security Council member tells Hersh. "The neocons still think they can pull the rabbit out of the hat in Iraq," a former intelligence official says. "What's the plan? They say, 'We don't need it. Democracy is strong enough. We'll work it out.'"

Israel has a longstanding relationship with the Kurds, whom they regard as one of the few non-Arab allies in the area. The Iraqi Kurds, who played a key role in providing the United States with intelligence ahead of the war, have been angered by the United Nations resolution on Iraq earlier this month. The resolution did not affirm the interim constitution that granted them minority veto power in a permanent constitution and so could potentially leave them sidelined.

One Turkish official told Mr Hersh that Kurdish independence would be calamitous for the region. "The lesson of Yugoslavia is that when you give one country independence everybody will want it. Kirkuk will be the Sarajevo of Iraq. If something happens there, it will be impossible to contain the crisis."