Taiwan's High Court ordered all ballot boxes sealed Sunday as thousands of protesters demanded a recount of President Chen Shui-bian's (searchre-election, saying it was marred by voting irregularities and an apparent assassination attempt that wounded the incumbent.

The court said it was sealing the boxes to preserve evidence, but it did not order a recount of Saturday's vote as requested by challenger Lien Chan (search). The opposition also said it would seek to nullify Chen's narrow victory Saturday, arguing he unfairly received sympathy votes because of the election-eve shooting, which remained unexplained.

Chen, who campaigned on a China-bashing platform, and Vice President Annette Lu (searchwere shot and slightly wounded while riding in an open Jeep on Friday in Chen's hometown of Tainan.

Nobody has been arrested, and police have not identified any suspects. A $718,750 reward was offered for information leading to an arrest.

Chen won Saturday's election with 50.1 percent of the vote compared to 49.9 percent for Lien -- a margin of just 30,000 votes.

But Taiwan's first-ever island-wide referendum, also held Saturday and championed by Chen, failed because many voters decided to boycott it. The ballot question was fiercely opposed by China, which saw it as a rehearsal for a vote on Taiwan independence. China and Taiwan split amid civil war in 1949, and China wants the island to rejoin the mainland.

Lien has pushed for a more conciliatory approach toward China. His party argued that Chen did not have the legal authority to call the referendum and successfully rallied Taiwanese to skip the vote.

About 10,000 demonstrators gathered in Taipei clamoring for an immediate recount, police said.

Speaking to the protesters, Lien said he was demanding that the government form a special task force with medical and criminal experts to investigate the attack on Chen and its influence on the election.

Late Sunday night, popular Taipei Mayor Ma Ying-jeou, who is also a high-ranking Nationalist official, addressed the protesters and suggested they should head home. He said police would avoid using force to clear out the area.

"We'll be extremely soft and just let people leave on their own, go home and rest," Ma told reporters.

Hours later, the crowd dwindled to just a few hundred people.

Politicians on both sides appealed for calm after mobs scuffled with police and pushed down barriers in the cities of Taichung and Kaohsiung. No serious injuries were reported.

Confronted with doubts about the shooting, Chen's office released photographs Sunday that showed him on an operating table being treated for a wound to the abdomen. In one frame he is talking on a mobile phone while doctors are working on him.

Earlier pictures released to media showed a long red gash on Chen's abdomen, apparently the wound from the bullet that struck him.

Presidential Office spokesman James Huang said officials released the pictures to stop speculation that the injury was faked to win sympathy votes for Chen.

"Some people said we faked this, that the pictures we released earlier only showed a belly," Huang told reporters. "If we wanted to use the incident to influence the election, we could have made these pictures public then to win sympathy. We did not because we didn't want to spark an outcry."

Meanwhile, prosecutor Cheng Hsiao-kuei said DNA tests showed that two bullets found after the shooting were those that injured Chen and Lu. It was not clear if they came from the same gun, Cheng said.

"One bullet slug was left between the president's underwear and his shirt" after the bullet grazed his stomach, she said, displaying pictures of holes punched through the president's clothes. The bullet that hit Lu in the knee was found in the Jeep.

Police interviewed shopkeepers along the president's route and were checking security tapes, but so far had no leads on the shooter's identity, said Tainan chief prosecutor Wang Sen-jung.

Officials in the southern city of Tainan said they would honor a request by Lien's campaign to maintain potential evidence for use in any legal case. Lee Wen-hsien, head of Tainan's administrative court, said that included the president's medical records, X-rays and eight hours of videotape from the emergency room.

After the election results were announced Saturday night, Lien immediately raised questions about more than 330,000 ballots that allegedly were spoiled.

Television footage later showed court officials stacking bags full of ballots, then stuffing them inside cardboard boxes that were taped shut to comply with the court decision.