Updated

Taiwan's ruling Nationalist Party won three out of five mayoral races Saturday, providing a boost for President Ma Ying-jeou's policy of improving relations with China ahead of the island's 2012 presidential poll.

But the main opposition Democratic Progressive Party, which wants to slow the process of reconciliation with the mainland, won about 50 percent of the overall mayoral vote, signaling that it will provide strong opposition to Ma's expected re-election bid — stronger by far than seemed possible only six months ago.

With 95 percent of the votes counted, the Central Election Commission results showed the Nationalists had insurmountable leads in Taipei, the new Taipei suburban constituency of Xinbei, and the central city of Taichung. DPP candidates were in unassailable positions in two large cities in the party's southern heartland — Kaohsiung and Tainan.

Together the five constituencies account for about 60 percent of Taiwan's population of 23 million.

The commission said the DPP's overall share of the mayoral vote stood at 49.9 percent, against 44.2 for the Nationalists and 5.9 percent for independents, compared to the 43 percent the DPP candidate garnered in the five constituencies in the 2008 presidential poll. Much credit for the comeback goes to party Chairwoman Tsai Ing-wen, who while losing in Xinbei — by about five percentage points — now emerges as a credible candidate for the party's presidential nomination in 2012.

Her main DPP rival, party veteran Su Tseng-chang, 63, lost by an unexpectedly high 12 percentage points in Taipei to incumbent Hau Lung-bin. The result may well put an end to any presidential nomination hopes for Su.

Conceding defeat in Xinbei, the American and British-educated Tsai said she was learning the populist approach that DPP candidates seem to favor in presidential campaigns.

"The citizens of Xinbei have turned me from a university professor, a member of the elite, into an accessible, personable, crowd-embracing politician," she said. "I really appreciate that."

Saturday's voting took place in the shadow of unusual election eve violence in the Taipei suburb of Yung Ho, where an alleged gangster opened fire at a Nationalist campaign rally, killing 29-year-old Huang Yun-sheng and seriously wounding Lien Sheng-wen, son of former Vice President Lien Chan.

Lien, the scion of one of Taiwan's most powerful political families, is being treated in a Taipei hospital.

Lin Cheng-wei, 48, was taken into custody in connection with the attack. He told reporters that he had targeted local city council candidate Chen Hung-yun because of a dispute between Chen and Lin's father.

Acts of violence are uncommon in election campaigns in Taiwan, which began a gradual transition from a one-party dictatorship to vibrant democracy in the late 1980s. Violence by Taiwan's gangs is also limited, though they exercise considerable political influence, particularly on county governments.

With the local elections out of the way, the attention of Taiwan's heavily politicized population will now turn to the presidential poll in March 2012, which is expected to be fought largely on the issue of Taiwan's relations with China, from which the island split amid civil war in 1949.

Harvard-educated Ma, 60, favors expanding Taiwan's already robust commercial ties with the mainland, and if re-elected, could begin political talks with Beijing.

In contrast, the DPP wants to slow the pace of economic convergence across the 100-mile (160-kilometer) -wide Taiwan Strait and would likely close the door on political dialogue with China's Communist government. That might worry the United States, which has applauded Ma's success in helping ease tensions in one of Asia's traditional flash points.

Still, compared to Ma presidential predecessor Chen Shui-bian, Tsai is regarded as a moderate on China policy, eschewing his hard-line pro-independence positions in favor of a much more measured approach.

Tsai, 54, is thought to have considerable appeal among the same centrist voters who put Ma over the top in 2008.