* Georgia and Russia resume talks after Moscow walkout
* Ban Ki-moon issues U.N. report on Abkhazia mission
(Adds quotes from U.N. Secretary-General report)
GENEVA, May 19 (Reuters) - Georgia and Russia resumed security talks on Tuesday after international mediators and a U.N. report helped nudge Moscow's negotiators back to the table, officials said. "They have started," a U.N. spokeswoman in Geneva said shortly after the closed-door talks resumed.
Delegations from Russia and the Moscow-backed rebel region of South Ossetia had withdrawn from the two-day talks in Geneva on Monday citing the refusal of another Moscow-backed rebel region, Abkhazia, to attend, due to a delay in the U.N. report.
In the report on the U.N. mission in Abkhazia, U.N. Secretary-General Ban Ki-moon said tensions between Georgia and Russia were weighing heavily on the region and that talks to date "have helped to maintain a relative calm" there.
It cites the official title of "United Nations Observer Mission in Georgia" but otherwise skates round the sensitive question of whether Abkhazia is part of Georgia or not.
"I hope that these efforts can lead to the establishment of a more stable security regime in the area," Ban said.
It is the fifth session of talks between Russia and Georgia since September following their brief war in August over South Ossetia.
Tensions remain around areas of South Ossetia and Abkhazia, particularly Akhalgori in South Ossetia and the Kodori Gorge and Gali regions of Abkhazia.
The U.N. deploys 129 military observers, drawn from 30 states, and 16 police officers in Abkhazia.
Ban's report recommended that security zones with no armed forces or military equipment be enforced for 12 km (8 miles) on both sides of the ceasefire line, and restricted zones with no heavy military equipment for another 12 km on each side.
He also called for regular U.N. monitoring of conditions in the Kodori valley and regular meetings between Russian and Georgian officials to maintain calm and stability. (Reporting by Stephanie Nebehay and Laura MacInnis; Editing by Jonathan Lynn)
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