A historic trip to China by the head of Taiwan's opposition party began Tuesday with a flurry of eggs and punches from angry supporters of the island's president at Taipei airport. Hours later, he was welcomed with flowers and speeches by Chinese communist officials who hailed his arrival as a sign of reconciliation.

The contrasting treatment underscores controversy surrounding the visit by Nationalist Party Chairman Lien Chan (search), the most prominent Taiwanese political figure to come to the mainland since the two sides split amid civil war in 1949.

Lien says his journey aims to lower tensions between the sides. Detractors say he is selling out Taiwan's interests and allowing Beijing to exploit divisions within Taiwanese society.

"Taipei and Nanjing are not too distant, but it still took 60 years to come here," Lien said on reaching the eastern city of Nanjing. "It certainly took too long to make the journey."

It wasn't an easy journey.

Nationalist supporters seeing Lien off at the airport in Taipei, Taiwan's capital, scuffled with backers of President Chen Shui-bian (search). Chen's party wants formal independence for Taiwan in defiance of the Nationalist and communist goal of independence between the island and mainland.

The rival groups detonated fireworks and blew air horns while shoving, kicking and punching each other. Lien supporters, gripping flags, tried to break through a police cordon but were pushed back.

Lien's visit is the first by a Nationalist leader since the party, which once ruled both Taiwan and China, fled the mainland following its defeat by the communists. It includes a meeting Friday with Chinese President Hu Jintao (search) — the first encounter between leaders of the two former enemies in six decades.

Less than 20 years ago, the visit would have been unthinkable. The Nationalists — who ruled Taiwan for five decades until losing power in 2000 — often jailed people who were sympathetic to the communists. Until the late 1980s, they banned Taiwanese from visiting the mainland.

But the tensions began to ease in the early 1990s, and Taiwanese tourists and businesses started flocking to the mainland. After losing the presidency, the Nationalists began pushing for closer ties with China, partly out of their shared opposition to Chen.

Referring to their newfound common ground, communist official Li Yuanchao praised Lien's visit as being "profoundly important for maintaining peace and stability and stopping the separatist plotting of the Taiwan independence forces."

"Chinese people at home and abroad have bestowed great importance," on the visit, Li, the governor of Jiangsu province — which includes Nanjing — told Lien in a meeting Wednesday night.

Lien, accompanied on the trip by his wife, planned to pay respects at the grave in Nanjing of Nationalist founder Sun Yat-sen (search) — claimed by both sides as their revolutionary forefather — before traveling to Beijing.

The eight-day visit comes a month after tensions rose over China's passage of a law allowing for a military attack on Taiwan if the island declared independence. Hundreds of thousands of Chen supporters attended a rally protesting the law, and the United States, Taiwan's chief military backer, expressed concerns over new tensions.

Lien didn't mention the law but said he hoped to discuss "the common future of both sides across the (Taiwan) Strait."

Analysts have disagreed on whether Lien's trip will help ease China-Taiwan tensions. Some say Beijing may be willing to trust Lien, who has served previously as foreign minister, premier, and vice president. That could allow for breakthroughs such as more direct transport links between them, they say.

"Lien's visit opens a new channel for ... direct dialogue between top leaders of political parties on both sides," Hung Gash, a professor at People's University in Beijing, was quoted as saying by the official Xinhua News Agency.

But others say Chinese leaders are using Lien to widen the schisms in Taiwanese society.

After losing presidential elections in 2000 and 2004, Lien is also seen as looking for some achievement to burnish his legacy as party leader. Lien was also due to visit Shanghai and his birthplace of Xi'an in western China before returning home.

Chen's government has criticized Lien's China trip and threatened to charge him with treason if he signs any deals without government authorization. But the president has mellowed in recent days, saying Lien could use his tour to "toss a stone to test the water" of reconciliation.

Lien's deputy party chairman visited Beijing in March. Another leading opposition figure, James Soong, has accepted an invitation to visit the mainland and his party says he might come next month.

The last time leaders of the Nationalist and Communist parties met was 1945, when Nationalist dictator Chiang Kai-shek (search) and Mao Zedong (search), then a guerrilla, held talks on forming a government.

Those negotiations failed and four years later, the communists drove Chiang and his Nationalists to Taiwan.