By Patrick Worsnip

UNITED NATIONS, Jan 7 (Reuters) - Morocco and the Polisario independence movement headed on Monday into fresh talks over Western Sahara as Polisario warned that failure could rekindle war in a region trying to contain al Qaeda-linked violence.

The U.N.-sponsored negotiations in Manhasset, near New York City, are the third round to tackle Africa's longest-running territorial dispute since the two sides submitted rival proposals for the resource-rich region last April.

Morocco took control of most of Western Sahara in 1975 when colonial power Spain withdrew, prompting a guerrilla war for independence that lasted until 1991 when the United Nations brokered a cease-fire and sent in peacekeepers.

Moroccan and Polisario negotiators were to have dinner together at Manhasset on Monday evening before conducting the talks on Tuesday and Wednesday. However, neither they nor U.N. officials saw much likelihood of a major breakthrough.

Polisario, which is backed by Morocco's regional rival Algeria, said last month war may restart if the talks fail to reach accord on whether Western Sahara should be independent or an autonomous region of Morocco.

"It will be the last opportunity Polisario offers Morocco," Polisario's envoy to Algeria Mohamed Yasslim told Algeria's main Arabic-language al Khabar daily in a recent interview.

"Preparations for war are afoot at all levels."

Analysts say, however, war is unlikely for now as Polisario relies heavily on Algeria, which has no desire to escalate regional tensions.

North African countries are under pressure to settle their differences in order to better deal with growing violence by al Qaeda-linked radical Islamists.

Algeria has suffered a series of deadly suicide bombings since early last year. The latest on Dec. 11 killed 37 people, including 17 U.N. staff in Algiers.

NO CONTACT BEFORE NEW TALKS

The desert territory of 260,000 on Africa's Atlantic coast contains phosphates and rich fishing banks and may have offshore oil.

Rabat is trying to convince Polisario to accept its plan for Western Sahara to be an autonomous part of Morocco. Polisario proposes a referendum among ethnic Sahrawis that includes an option of independence.

Moroccan officials have cautioned against over-optimism ahead of the talks. "We do not expect a breakthrough from the upcoming talks," a senior Moroccan government official said.

In New York, Polisario U.N. representative Ahmed Boukhari also played down expectations. "Unfortunately we hear Morocco is not going to change its position," he said.

Rabat and Polisario have lined up the same officials who took part in previous talks in June and August that ended with no tangible outcome, prompting the U.N. Security Council to urge them to put more effort into the negotiations.

U.N. Secretary-General Ban Ki-moon has complained that the two sides are not negotiating, merely restating positions.

"No contact was made between Rabat and Polisario since they wrapped their latest talks in August and that does not give hope they would advance towards an acceptable solution soon," said a senior Western diplomat.

No state recognizes Morocco's rule over the territory but the U.N. Security Council is divided with some non-aligned states backing Polisario, and France and the United States supporting Morocco. (Additional reporting by Lamine Ghanmi in Rabat; editing by Bill Trott)

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