Islamabad - Pakistani President Asif Ali Zardari on Tuesday left for Beijing to garner economic and commercial assistance as the security situation along the Afghan border undermines the country's relations with the United States.

The four-day visit is Zardari's first official bilateral visit since his election to the presidency in September. However, he had already met US President George W Bush on the sidelines of the United Nations General Assembly session last month.

The visit demonstrates the government's resolve to take this "time-tested" relationship to "new heights," the country's foreign ministry said in a statement earlier.

Zardari's visit comes at a time when the relations between Washington and Islamabad, two key allies in the international fight against terrorism, have been strained due to increasing US drone attacks on suspected militant hideouts inside Pakistan.

A number of agreements are expected to be signed between the neighbours.

Some media reports said Pakistan, which celebrates China as its "all-weather friend," was likely to seek a civil nuclear deal with the Communist state on the pattern of a recent arrangement between the US and Pakistan's archrival India.

China has already helped Pakistan build a 300-megawatt nuclear power plant while work on a similar facility is under progress.

Zardari is also expected to seek a soft loan of 500 million to 1.5 billion US dollars from the Chinese government to avoid a looming default on external debts, the Financial Times reported.

Zardari's engagements include meetings with Chinese President Hu Jintao, Prime Minister Wen Jiabao and National People's Congress Chairman Wu Bangguo, besides interactions with leaders in the financial and corporate sectors.

According to official figures, annual trade between the two countries has already crossed 7 billion US dollars, and both sides are looking forward to take it to 15 billion US dollars by 2011. A Free Trade Agreement between them has been in force since last year.

Beijing supports Pakistan in its strategic infrastructural development projects, and has also funded the now-commissioned deep sea port at Gwadar.

China is also the biggest weapons supplier to Pakistan and the two countries have also jointly developed the JF-17 Thunder jet fighter and K-8 jet trainer aircraft. (dpa)