The common assembly has not met since the Kurdistan Democratic party (KDP) and the Patriotic Union of Kurdistan (PUK) fell out in 1994 to fight each other and set up separate autonomous administrations, respectively adjoining Turkey and Iran.

The agreement, which essentially commits the two sides to implement a 1998 peace deal, will be welcomed by the US, which has been working to unify the disparate Iraqi opposition groups.

A KDP statement said the two Kurdish groups had agreed to strengthen ties with other Iraqi opposition groups "in the interest of the future of Iraq". Western officials said the two groups' leaders were also keen to appeal to their own constituents, who have seen no benefit from the duplication and confrontation inherent in two rival administrations.

The agreement was, however, expected to cause unease in Turkey, a Nato member whose support is seen as crucial to any US military intervention in Iraq.

Turkish diplomatic sources were yesterday quoted by local media as saying that the regional assembly had always been a worry for Ankara, which saw it as the "seed of a possible Kurdish state".

Officials are wary of moves they fear could stir separatist longings among Turkey's Kurds.

Kurds both in and outside Turkey say they do not want an independent state. But in recent months the KDP and ministers from the ultra-nationalist wing of Turkey's three-party coalition government have traded inflammatory rhetoric in the run-up to Turkish general elections.

Safeen Dizayee, the KDP representative in Turkey, said yesterday, however, that his organisation's leadership had met the Turkish foreign ministry as part of efforts to "mend fences. and avoid misunderstandings".