BEIJING (Reuters) - China told Mongolia to forbid the Dalai Lama's planned arrival there on Friday, suggesting the Tibetan spiritual leader's trip could harm Beijing's relations with its northern neighbor.

China regards the Dalai Lama as a separatist, though he says he merely seeks genuine autonomy for his Himalayan homeland Tibet, which Communist Chinese troops "peacefully liberated" in 1950.

"We strongly urge Mongolia to act by keeping in mind the big picture of maintaining the stable development of bilateral relations and to keep their promises made on this issue," Chinese Foreign Ministry spokesman Geng Shuang said.

"Do not allow the Dalai Lama to visit. Do not support or facilitate the separatist activities of the Dalai clique," Geng said at a regular press briefing.

Mongolian media have said the Dalai Lama is expected to arrive Friday afternoon.

After the Dalai Lama's visit to Mongolia in 2006, China canceled flights between Beijing and Ulaanbaatar. Flights later resumed.

Beijing frequently expresses its anger with countries that host the 81-year-old Nobel Peace Prize winner, who fled to India in 1959 following a failed uprising against the Chinese.

Rights groups and exiles accuse China of trampling on the religious and cultural rights of the Tibetan people, charges strongly denied by Beijing, which says its rule has brought prosperity to a once backward region.

(Reporting by Beijing Newsroom; Writing by Paul Carsten; Editing by Richard Borsuk)