BEIJING (Reuters) - The United States stressed on Thursday that it opposes Taiwan plans to hold a referendum on U.N. membership, while China urged Washington to help oppose the vote that it calls a dangerous provocation.

Supporters of Taiwan's main opposition Nationalist Party (KMT) celebrate after the Taiwan legislative elections outside the party's headquarters in Taipei, January 12, 2008. REUTERS/Nicky Loh

Speaking before regular high-level talks with China, U.S. Deputy Secretary of State John Negroponte pointedly criticized the vote planned for March in which Taiwan’s independence-leaning President Chen Shui-bian wants approval to seek U.N. membership under the name “Taiwan”.

China regards Taiwan as a breakaway province that must accept reunification and calls the referendum a provocative bid to create formal independence for the island.

“From the perspective of the United States, the conduct of such a referendum is a mistake,” Negroponte told reporters, echoing comments made in December by U.S. Secretary of State Condoleezza Rice.

“We think it is a provocative policy on the part of the Taiwanese authorities.”

Negroponte made the remarks ahead of two days of talks with Chinese Vice Foreign Minister Dai Bingguo that will cover Taiwan and other diplomatic hotspots, including North Korea and Iran.

China indicated that Taiwan remains its top worry and it wants Washington efforts to help stifle Chen’s plans for the vote alongside presidential elections on the island.

Both Chinese Premier Wen Jiabao and Foreign Minister Yang Jiechi raised the referendum when meeting Negroponte on Wednesday, the Communist Party’s official People’s Daily said.

“Under current circumstances, opposing secessionist activities such as the referendum more firmly is vital for peace and stability across the Taiwan Strait and overall China-U.S. relations,” Yang was quoted as telling Negroponte.

SENSITIVE ISSUE

Wen told Negroponte that Washington should “properly” deal with sensitive issues such as Taiwan.

China has claimed sovereignty over self-ruled Taiwan since the end of the Chinese civil war in 1949. It has vowed to bring the island back under mainland rule, by force if necessary.

The United States switched diplomatic recognition from Taipei to Beijing in 1979, recognizing “one China”, but is obliged by the Taiwan Relations Act to help the island defend itself and is its biggest ally and arms supplier.

“This is an issue that must be dealt with by peaceful means,” Negroponte told reporters.

Taiwan’s main opposition Nationalist Party (KMT) thrashed the ruling Democratic Progressive Party (DPP) in legislative elections on Saturday, strengthening its bid to recapture the presidency in March and heralding better relations with China.

But China remains jittery, especially with Beijing’s Olympic Games in August drawing additional attention to its actions.

Taiwan, under its official name the Republic of China, lost its U.N. seat to China in 1971. Repeated attempts by Taiwan to rejoin the world body have failed.

The use of “Taiwan” -- rather than Republic of China -- in Chen’s latest campaign is viewed as particularly inflammatory by Beijing, which sees it as firming up the pro-independence claims.

Taiwan is recognized by just 23 mostly small, poor countries around the world, against 171 that recognize China.

Late last year, China abruptly cancelled a U.S. naval port call to Hong Kong, possibly reflecting unhappiness over U.S. military activities around Taiwan.

Chinese Foreign Ministry spokeswoman Jiang Yu said her country approved of Washington’s opposition to the referendum.

But she also told a news conference that the United States should “proceed with caution” in the Taiwan Strait, where U.S. navy ships sometimes pass, calling the area “highly sensitive”.