North Atlantic Treaty Organisation (Nato) leaders head for Istanbul next week hoping to avoid new splits over Iraq, amid simmering discord over calls for it to play a larger role there at a time when it is already stretched in Afghanistan.

US-led pressure for the Alliance to do more in Iraq comes as it battles to meet its commitments to extending a peacekeeping force beyond the Afghan capital Kabul, to help secure the country ahead of planned September elections.

In Istanbul next Monday and Tuesday Nato is expected notably to declare itself ready to fulfil those pledges -- specifically to set up five Provincial Reconstruction Teams (PRTs) in northern Afghanistan, as well as sending reinforcements for the polls.

But the battle to secure the resources from Nato member states has been painfully difficult, a process which risks compromising the credibility of an Alliance seeking to present itself as a key force in the global war on terror.

Nato took command of the International Security Assistance Force (ISAF) in Afghanistan in August 2003, in its first-ever mission outside Europe, and was given the United Nations green light a short time later to extend it outside Kabul.

Eight months later, it is in charge of only one PRT, in the northern city of Kunduz, run by the German army.

"Whenever we enter into a political commitment to undertake an operation, we must have a clear idea beforehand as to what forces we have available to honour this commitment," Nato chief Jaap de Hoop Scheffer said in London last Friday.

Visibly tired of having to go cap in hand to beg for hardware and troops, he demanded that Nato leaders in Istanbul "make sure that our means match our ambitions."

On Iraq, Nato has never really recovered from its divisions in the run-up to last year's war -- when it was plunged into the most serious crisis in its 55 year history amid a split between pro- and anti-war factions.

Sixteen months after that crisis, the Americans are pushing for Nato to take on a bigger role than its current one of providing logistical support to Poland in running its sector of a multi-national stabilisation force.

But France and Germany -- which sparked the February 2003 crisis -- are again resisting the call.

To add to the potential for rifts, the Istanbul summit comes two days before the June 30 handover of sovereignty from the US-led occupation force to an interim Iraqi government.

With Paris and Berlin blocking any suggestion of Nato troops on the ground, one key option under consideration is for the Alliance to help train Iraqi troops. Officials stress this would only be possible if Iraq requested it.

De Hoop Scheffer -- attending his first summit as Nato secretary general, and the first since the alliance's April expansion from 19 to 26 members -- says that, if this were the case, it would be difficult to "slam the door in their face."

Decisions expected at the Istanbul summit include the formal end to the Nato-led SFOR mission in Bosnia-Hercegovina, which will be handed over to the European Union at the end of the year.

Nato will also trumpet its new strategy of strengthening cooperation with Muslim states around the Mediterranean basin, although leaders of these countries will not be in Istanbul.

Security will be tight for the two-day summit, amid fears of terrorist attacks and concerns over demonstrations -- which began as early as yesterday when police had to use water cannon, tear gas and armoured vehicles to disperse activists throwing petrol bombs to protest the summit. – Sapa-AFP.