BEIJING -- European Union leaders urged China on Tuesday to open its markets, join in persuading Iran to negotiate over its nuclear program and help end bloodshed in Syria as they held a summit delayed by Europe's debt crisis.
Leaders of the two sides pledged to boost trade and to start negotiations on an investment treaty.
But at a news conference, EU officials and Chinese Premier Wen Jiabao expressed differences on issues from trade to human rights.
European Council President Herman Van Rompuy said he and European Commission President Jose Manuel Barroso pressed during talks with Wen for China to open its markets.
"I repeatedly stressed the need for a level playing field for European business, including better market access for European companies, protection of investment and intellectual property and our concerns about protectionism," said Van Rompuy.
Europe is China's biggest trading partner but European companies and business groups complain Beijing is trying to limit their access to promising industries and favors Chinese rivals in violation of its free-trade pledges.
The summit came after rating agency Moody's on Monday downgraded its credit ratings on Italy, Portugal and Spain. France, Britain and Austria kept their top ratings but their outlooks dropped to "negative" from "stable," meaning they too might be downgraded.
The meeting was originally scheduled for October but was postponed due to emergency meetings on the European debt crisis.
China's stake in Europe's economic health has increased as Chinese companies step up investment there. The biggest Chinese producer of construction equipment agreed this month to acquire Germany's Putzmeister, a maker of concrete pumps.
Wen, appearing with Van Rompuy and Barroso at the Great Hall of the People, the seat of China's legislature, said Beijing is ready to "increase its participation" in resolving Europe's debt crisis but made no financial commitments.
Wen said earlier this month during a visit by German Chancellor Angela Merkel that Beijing was considering contributing to two European bailout funds but the government has given no indication of progress toward that.
On global affairs, Van Rompuy said the EU supported efforts of the Arab League to end violence in Syria and appealed to "all members of the U.N. Security Council" -- a group that includes China -- to "act responsibly."
China, along with Russia, has been criticized for vetoing a Security Council resolution that would have pressed Syrian President Bashar Assad to step down. China says the council vote was called before differences over the proposal were bridged.
Wen said the most urgent issue in Syria is to "prevent war and chaos."
"China is absolutely not protecting any party, including the government of Syria. The future of Syria is for the Syrian people to decide," the premier said.
Van Rompuy also nudged Beijing to help bring Iran to the negotiating table over its nuclear program. Western governments suspect Tehran is trying to develop nuclear weapons but the Iranian government denies that.
China, the biggest buyer of Iranian crude, has rejected U.S. and European efforts to impose an oil embargo to force Tehran to negotiate.
"I shared with Premier Wen our deep concern on the Iranian nuclear program and I explained to him that our actions and sanctions are aimed to bring Tehran back to the negotiating table," Van Rompuy said.
Wen said China and Europe had common concerns in preventing the spread of nuclear weapons and appealed for a negotiated settlement but gave no sign Beijing might joint in economic pressure on Tehran.
Van Rompuy said the two sides also discussed human rights but gave no details.
"As a partner and friend of China, I've also expressed the serious concern Europeans have for these achievements (in combating poverty) to be accompanied by similar progress in respecting universal human rights and rule of law," he said.
Wen said China was willing to discuss human rights but "such a dialogue should be carried out on the basis of mutual respect and objectivity in order to build further trust."
Responding to spiraling unrest in Tibetan areas, the premier defended Beijing's policies on Tibet, saying the government respects traditional culture. He said China has invested heavily in Tibet and will continue to do so.
"The people living in Tibet are an important component of the big family of ethnic groups in the Chinese nation," Wen said. "Any attempt to incite a small number of monks to take radical moves to undermine stability in the Tibet Autonomous Region is not in the interests of people living in Tibet and such an attempt has no popular support."