By Mark John

BRUSSELS, June 12 (Reuters) - NATO chiefs will grapple on Thursday with new obstacles facing the international security presence in Kosovo, but are due to reaffirm pledges to maintain 16,500 peacekeepers there as long as needed.

Alliance defence ministers meeting in Brussels will also hear a U.S. call for help to beef up the police training effort in Afghanistan, and will urge their Russian counterpart to ease tensions with Georgia over the breakaway Abkhazia region.

Kosovo's disputed Feb. 17 secession from Serbia passed off relatively calmly but has left a series of questions over the complex security arrangements in the territory.

Not only is a planned 2,200-strong European Union police mission already facing months of delays after resistance from Russia in the United Nations, but obstacles have emerged over longstanding NATO plans to train Kosovo's own armed force.

Diplomats said Turkey was concerned the training effort would mean sharing sensitive information with EU member Cyprus, the island at the centre of decades of Turkish-Greek tension.

Separately, some of the countries which have not recognised Kosovo -- such as Spain -- are also unhappy with internal NATO planning documents for the training mission which they argue use terminology assuming Kosovo's independent statehood.

"I do not see a happy end to this just yet," said one NATO diplomat, playing down prospects for consensus in Brussels over arrangements for NATO help in creating a 2,500-strong, lightly armed "Kosovo Security Force" (KSF).

The wrangling comes just days before the June 15 date when Kosovo's new constitution comes into force and when questions over the new security make-up for the territory were long supposed to have been settled.

BURDENED

Allies fear that the delay in a planned handover from the United Nations to the EU of police tasks in Kosovo could mean that alliance troops are burdened with duties such as riot control for which they have not been trained.

U.N. Secretary-General Ban Ki-moon is expected to announce new proposals in coming days that will allow the EU mission to launch around September, but EU foreign policy chief Javier Solana said on Wednesday he had not received any word from Ban.

Despite their concerns, NATO officials stress NATO's core peacekeeping force in Kosovo will remain there.

"NATO has been the backbone of stability in this period of transition and it is essential that continues," said a senior U.S. official.

U.S. Defense Secretary Robert Gates is also expected to use the Brussels talks to urge allies to fill shortfalls in NATO's Afghan security force. Commanders insist it is under-resourced despite having added several thousand troops for a total force strength of some 52,000 in recent weeks.

He will notably urge European allies to offer mentoring units to chaperone and monitor newly-trained Afghan police as they return to their beats, the senior U.S. official said.

NATO defence chiefs will urge their Russian counterpart Anatoly Serdyukov on Friday to help ease tensions with Georgia over the breakaway Georgian region of Abkhazia.

Tbilisi accuses Moscow of supporting the rebels and Russia accuses Georgia of planning to invade the region. Interfax on Saturday quoted the Russian Ministry of Defence as saying it would withdraw within two months 400 soldiers sent to repair damaged railway lines, a deployment that had angered Georgia. (Additional reporting by Ingrid Melander; editing by Keith Weir)

AlertNet news is provided by