Amid rowdy street protests, Taiwan's leader shook hands and exchanged gifts Thursday with the most senior Communist Chinese official to visit the island. He later declared the trip a success but acknowledged that major disputes still exist between the rivals.

Taiwanese President Ma Ying-jeou met the Chinese envoy, Chen Yunlin, at a government guesthouse for five minutes. The historic meeting came five hours earlier than planned to avoid chaotic demonstrations by Taiwan independence groups that threatened to lay siege to the capital.

Ma praised a landmark agreement signed Tuesday that many believe will greatly ease tensions between Taiwan and China. The deal increases aviation and shipping links. It also included measures for better cooperation with food safety issues.

The two sides decided to hold high-level talks every six months and tackle financial issues in the next meeting.

But Ma added, "We can't deny that there still exists differences and challenges, especially regarding Taiwan's security and international status."

Chen has drawn daily protests since his five-day trip began Monday. On Wednesday, nearly 1,000 protesters surrounded blocked Chen from leaving a banquet dinner at a hotel until well past midnight.

Despite the protests, Chen's visit has signaled warming times between the two rivals. Marking those relations, Chen signed a deal around midmorning Thursday with Taipei Mayor Au Long-bin to swap rare wildlife with Beijing, offering two pandas to Taiwan in exchange for a Formosa sika deer and a Formosa serow, a goat-like animal.

China and Taiwan split when the Communists won a bloody civil war and took over the mainland in 1949. Beijing doesn't formally recognize Taiwan's government and insists the island must unify eventually. China has repeatedly threatened to use its massive military to force the Taiwanese to rejoin the mainland.

The Chinese envoy made a only a few remarks to Ma as he presented the Taiwanese leader with a painting of a horse.

"I offer this to you," he said.

Chen was careful not to address Ma by the title "president," sticking to Beijing's policy of avoiding any terms or symbols that suggest Taiwan is an independent country.

This angered many of the hundreds of protesters who gathered in the streets around the guesthouse, blowing air horns and scuffling with riot police armed with shields. After the meeting, the crowd began marching to the Presidential Office.

Chang Bang-ni, a 45-year-old businesswoman, said the Chinese envoy snubbed Taiwan by not calling the island's leader "president."

"This shows that China is only treating Taiwan like a local government," Chang said.

Another protester, Ko Kai-liang, accused Ma of embarrassing Taiwan by being too accommodating to the Chinese.

"Ma is sucking up to China by degrading Taiwan's sovereignty and this humiliates our country," said Ko, 40, who works for a chemical company.