Chinese Premier Wen Jiabao left Beijing Tuesday on an official visit to Pakistan, Bangladesh, Sri Lanka and India with the aim of increasing trust, friendship and cooperation with China's southern neighbors.

The visit, to last until April 12, is intended "to increase trust, deepen friendship, expand cooperation and map out future development with its southern neighbors," Chinese Foreign Ministry spokesman Liu Jianchao said earlier.

China has described its relationship with Pakistan as "all-weather, all-around cooperative partnership."

Wen is expected to meet with Pakistani President Pervez Musharraf and Prime Minister Shaukat Aziz, address a China-Pakistan business forum and the foundation-laying ceremony of the Pakistan-China friendship center in Islamabad. And the two countries are expected to sign a number of documents during Wen's stay in Pakistan.

The visit to Pakistan will "further strengthen the all-weather and time-tested friendship and strategic partnership between Pakistan and China," Pakistan's Foreign Office spokesman Jalil Abbas Jilani said on Monday.

Establishing a direct airline between Dhaka and Kunming will be conferred during Wen's visit to Bangladesh, according to Bangladeshi Ambassador to China Ashfaqur Rahman.

The airline from Dhaka, capital of Bangladesh, to Kunming, capital of southwest China's Yunnan Province, will be the first direct air link between the two countries.

Besides the Dhaka-Kunming air route, a couple of agreements and memorandums of understanding in various fields are expected to be inked during the visit.

In Sri Lanka, Wen is expected to visit some areas hit by the tsunami last December, according to Sri Lankan Ambassador to China Nihal Rodrigo.

"Hopefully a number of agreements will be signed, one on expansion of economic relations, and possibly a cultural agreement," said Rodrigo. "What we really expect is the complete consolidation of the existing relationship, strengthening areas like the fishery industry and seeking other means to develop our economic relationship, such as tourism."

China and India may touch upon the border issue during Wen's visit to India, his last leg of the trip. An issue left over from history, the border issue "does not hinder the overall development of Sino-Indian friendship and cooperation," a senior Chinese diplomat said.

Chinese Vice-Foreign Minister Wu Dawei said China and India have held four meetings within the special representative consultation mechanism, and the fifth meeting is expected to be held during Wen's visit to India. The two sides may reach consensus during the meeting, said Wu.

Indian Ambassador to China Nalin Surie said China and India can be friends, competitors and cooperative partners.

"Our two countries are in the process of rediscovering each other," he said, calling upon the peoples of the two countries to promote exchanges.

Besides meeting with Indian leaders, Wen will also visit an IT center in India, give a speech in New Delhi and attend the inauguration of the China Culture Month in India.

In 2004, China's trade volume with India was 13.604 billion US dollars, up 79.1 percent from a year earlier.

Meanwhile, the Chinese Premier will attend the opening ceremony of the fourth Foreign Ministers' Meeting of Asia Cooperation Dialogue in Islamabad on April 6, at which he will deliver a keynote speech.

Wen's entourage includes Foreign Minister Li Zhaoxing, Minister of Education Zhou Ji, Minister of Commerce Bo Xilai, Director of the Research Office of the State Council Wei Liqun, among others.