NEW DELHI, Nov 17 (Reuter) - India and China have pledged to strengthen economic ties and resolve a three-decades-old border dispute, the Foreign Ministry said on Friday during an upbeat visit by a powerful Chinese official.

"No force can separate India and China," the ministry quoted Qiao Shi, the head of China's parliament, as telling the leader of India's lower house late on Thursday.

The five-day visit by Qiao, one of the seven most powerful men in China's top decision-making Politburo, is the first to India by the chairman of the National People's Congress.

Foreign relations analysts said the visit, which was marred at the outset on Wednesday by protests by Tibetan refugees, was part of a warming trend in bilateral relations.

"There is a steady improvement in Indo-Chinese relations," said Bhabani Sen Gupta, executive director of the Centre for Research on International Change.

But there was no indication Qiao lent any support to India's drive to win a permanent seat on the United Nations' Security Council or to join the Asia-Pacific Economic Cooperation (APEC) forum, Sen Gupta said. Qiao met President Shankar Dayal Sharma, Prime Minister P.V.

Narasimha Rao, Foreign Minister Pranab Mukherjee and lower house speaker Shivraj Patil on Thursday before leaving for Agra on Friday. After Agra he was set to visit Bangalore and Bombay.

Business relations were high on the agenda of his meetings, according to a Foreign Ministry statement.

"What we have achieved together, particularly in the economic and commercial fields, is satisfactory but there is much potential for expanding our relationship in this area," the ministry quoted Qiao as saying.

"We must exchange what we have for what we need," he said. "The prospects for such cooperation are very encouraging."

A Foreign Ministry spokesman said: "China and India are exploring each other economically. There is a great potential for trade. This process, put in cold storage for a long time, is warming up."

Qiao and Mukherjee discussed a bilateral agreement, reached during a visit to China by Rao in 1993, to seek "border peace and tranquillity." In August, Delhi and Beijing agreed to pull back their troops from four border posts in India's northeastern state of Arunachal Pradesh, parts of which are claimed by China.

The decision followed two years of talks to ease tensions along the 4,000-km (2,500-mile) Himalayan border, cause of a brief war between the Asian giants in 1962.

Mukherjee, according to the ministry statement, said he hoped "the two sides would proceed to ultimately resolve problems arising out of (the) border dispute, which is complex and requires time and patience, to mutual satisfaction."

"Problems left over from history can be resolved, given goodwill and determination on both sides," Qiao said.

Sen Gupta said while Delhi and Beijing were moving closer together, there continued to be opposition from Indian strategic experts who claim China poses a military threat and do not want to alienate the United States.

"There is caution on the part of the Indian government to move quickly towards better and more productive relations. The Chinese appear to be more anxious to move forward," he said.

"This Indian government supports reasonably friendly relations and economic cooperation without giving it the glow of a revived partnership," Sen Gupta said.