Relations between Washington and Beijing are improving and they will need to work together in the face of the global economic slowdown, state media said in a commentary early Thursday.

Both sides had made "concerted efforts" to improve ties in the last 30 years, the Xinhua news agency said in an editorial, together making "important contributions to world peace and development."

"The two countries have made substantial progress in developing a multi-faceted and multi-level constructive partnership," the commentary said.

Relations had not always been smooth since diplomatic ties were officially established in 1979, it noted, urging both sides to "really cherish the current development result of their ties."

That was particularly pressing given the grave economic situation globally, the editorial said, and both sides had a duty to work together to stimulate world growth.

"The two sides should promote their bilateral ties onto a new level, further strengthen high-level exchanges, step up cooperation in various fields, and enhance coordination in macro-economic and financial policies."

The editorial did not comment specifically on what it expected from US president-elect Barack Obama, although it did note the 30th anniversary of ties coincided with the first year of his administration.

However, Obama, at the height of campaigning ahead of the November 4 elections, accused China of manipulating its currency in a letter to the National Council of Textile Organizations.

Obama called for China to change its foreign exchange policies to rely less on exports and more on domestic demand for growth.

The yuan's value has been a sensitive issue between China and the United States, which has accused Beijing of deliberately keeping its currency low to protect the competitiveness of Chinese export prices.

Human rights issues have also been a regular thorn in ties between Washington and Beijing.