Several incidents of harassment, culminating with the discovery of a bomb under a vehicle belonging to a British charity working with the Kurds, has now prompted that organisation to withdraw several of its expatriate staff.
'These are Iraqi attacks. They are trying to drive the aid agencies out, and the policy is working,' said Serchil Qazzaz, representative in Turkey of the Patriotic Union of Kurdistan (PUK). 'Foreign aid workers are afraid to leave their homes and I don't blame them.'
Incidents in the past month include gunfire against a United Nations building, the blowing up of a UN vehicle, a grenade tossed over a garden wall that badly injured two Austrian UN guards and a car-bomb which killed seven Kurds but was aimed at the French First Lady, Danielle Mitterrand.
Diplomats say only three large aid agencies remain - Save The Children, Care International and Caritas. 'There is now virtually no major relief effort in northern Iraq,' said one Western diplomat. 'Foreign funding is drying up. The Kurds can drift on through the summer if there is no new fighting and displacement. But they are pulling themselves up by their own bootstraps.'
This reality is a partial victory for Baghdad's campaign against the international aid effort for the Kurds since their dramatic exodus to the mountains of Turkey and Iran in April of last year. It also aims to undermine the democratically elected Kurdish 'executive authority' which, along with Kurdish guerrilla groups, now forms a quasi-independent government for at least 3 million Kurds.
Since the beginning, Iraq, diplomats and aid agencies have fought over the legitimacy of the UN operation and the six-month Memoranda of Understandings that provided a legal umbrella for relief work.
Even under these agreements Baghdad would delay or refuse visas for some relief workers. When US soldiers ran the Kurdish enclave, Iraqi officials were sometimes forced to issue them at gunpoint. But while the allied Provide Comfort force may still rule northern Iraqi airspace, they are only nominally present on the ground. 'There have been virtually no visas issued for two months,' said Joan Anderson of Save The Children. 'We're committed to continuing our programme, but we are trying to draw the attention of the UN to lack of protection.'
Diplomats say there is no sign of Baghdad signing an extension to the memorandum, part of its struggle against the United Nations and the allied powers. 'There's a trial of strength going on. The UN is not going to move. I think it's likely that we see a few shots fired,' said one European envoy in Ankara.
Private aid workers used to complain that the former main UN co-ordinating agency, the office of the United Nations High Commissioner for Refugees, kept deferring to Baghdad to retain its legitimacy. But diplomats say this deference has turned into paralysis under the UNHCR's replacement, Unicef.
What the UNHCR did accomplish in northern Iraq, especially in last summer's winterisation project, was often achieved by buying supplies in Turkey and driving them by road over the border. Since October, the Turkish route has become even more important because of the blockade imposed on the Kurds by Baghdad, multiplying the effect of existing UN sanctions on the whole of Iraq.
Bernard Kouchner, France's Minister for Health and Humanitarian Affairs, suggested building on the trans-border option to create a separate framework via Turkey for UN and international aid to the Kurds. But this requires political recognition of Kurdish separateness, something even the French Foreign Ministry, let alone Turkey, is not ready to contemplate.
For the time being, the only concession is tolerance by all sides of up to 1,000 lorries a day between Turkey and Iraq. Turkish lorry drivers get work, Iraq sells up to 20,000 barrels of smuggled diesel oil per day and the Kurdish 'executive authority' earns dollars 3m (pounds 1.5m) a month of transit taxes.
Mr Qazzaz of the PUK bought four lorries of cigarette papers and filters that Iraqi President Saddam Hussein shifted to the north at the start of the Gulf war. 'Turkey will not let them through. We could have made dollars 30-40m out of them to pay our people,' he said. 'There doesn't seem much the world can do against Iraq. But our people would prefer to starve than go back to Saddam.'