BEIJING, Jan 24 (Reuters) - China and Nauru re-established diplomatic ties on Wednesday, after the tiny Pacific island nation unexpectedly severed relations with its now former ally Taiwan in a move the United States described as "unfortunate".

The Pacific has become a source of intense competition for influence between Washington which has traditionally viewed it as its backyard, and Beijing, which has targeted Taiwanese diplomatic allies there.

During a ceremony in Beijing, China's Foreign Minister Wang Yi and his Nauru counterpart Lionel Aingimea formally signed a document to restore bilateral relations, with ties at the ambassadorial level resuming with immediate effect.

According to the document Nauru recognises that there is "only one China in the world" governed by the People's Republic of China and that Taiwan is an inalienable part of China.

Taiwan rejects China's sovereignty claim and accused it of trying to pressure Taiwan immediately after its recent presidential election with news of Nauru's switch.

Severing ties with Taiwan was "an independent political decision made by the Nauruan government," Wang told reporters after the signing ceremony.

"We are willing to share with Nauru the development opportunities brought by Chinese-style modernisation."

Aingimea said his country looked forward to their new relationship.

"It'll be built on strength, built on development strategy. It will have a synergy of policies. It will have good collaboration and shared governmental principles that both our countries enjoy," he said.

"The prospect is bright."

Photo from Reuters