A high-ranking US official has expressed hope that China will contribute more to the reconstruction of war-torn Afghanistan.

Robert Blake, US assistant secretary of state for South and Central Asian affairs, made a two-day visit to China.

Washington wants Beijing to "coordinate more" with its efforts in Afghanistan and Pakistan, US Assistant Secretary of State for South and Central Asian Affairs Robert Blake said on Tuesday after completing a two-day visit.

He made the remarks about a month before the international coalition forces' planned offensive against Kandahar, considered the spiritual home of the Taliban, in southern Afghanistan.

Blake, who discussed the South Asian situation with scholars and officials at the Ministry of Foreign Affairs, said: "China has an important stake in the success of these (international) efforts. And we welcome the opportunity to discuss ways China can contribute more both through investments and through assistance of various kinds." He did not specify the areas in which Washington hopes Beijing will do more.

Both NATO and Kabul have repeatedly called upon Beijing to reopen its 90-km border - which China sealed after 2001 - so that it can serve as a route for logistics supplies.

A recent Pentagon report on Afghanistan notes that "an array of measures suggest that the situation is little better overall than it was six months ago despite enormous expenditures of effort, money and lives by the American and international forces", The New York Times reported last week.

There were a total of 133,500 international service members in Afghanistan as of March 31, 87,000 of them US troops, the report said.

More American troops are due to arrive over the next three to four months, raising the number to 98,000.

As of March 20, there were 1,617 coalition deaths - including 951 from the US - since the 2001 invasion.

"The US hopes China to be as deeply involved as it can," said Hu Shisheng, a senior scholar of South Asia studies at the China Institutes of Contemporary International Relations.

"It's in accordance with (US President Barack) Obama's strategy, which seeks to involve regional powers in Afghanistan," he said.

Hu, who had a discussion with Blake on Monday, said the US official suggested that Beijing provide more aid in agriculture, education and training of officials.

"He (Blake) also noted that China and the US are yet to set up a regular information exchange mechanism on Afghanistan," Hu added.

China has been active in the reconstruction of Afghanistan since the US invasion in 2001 following the 9/11 terror attacks.

China Metallurgical Group Corp and China's top integrated copper producer, Jiangxi Copper Corporation, in July started a project in Logar, a province southeast of Kabul, to explore the vast Aynak copper mines. The US$4 billion investment is the biggest in Afghanistan's history.

China has also helped Afghanistan train dozens of minesweepers over the past year.

In late March, Beijing signed three deals with Kabul when Afghan President Hamid Karzai paid a state visit. They cover economic cooperation, technical training and the granting of preferential tariffs for Afghan exports.

Despite these efforts, Hu said China can do more in reconstruction, and pointed to India as an example.

India is one of the leading donors to Afghanistan, giving more than $1.2 billion since 2001, according to a recent DPA report.

China has offered more than $131 million in assistance to Afghanistan since 2002, Xinhua reported in March.

"China should actively contribute to helping Afghanistan with people's livelihood, economic growth and social stability," Hu said, noting it is in China's interests to do so.