``We think there are enormous benefits to the engagement policy we have with China to our national interest as far as security around the world and in region is concerned, whether it is North Korea or India-Pakistan...,'' White House press secretary Joe Lockhart told mediapersons here yesterday.

On the alleged Chinese espionage of obtaining the latest US nuclear weapon technology from the Los Alamos laboratory in the 1980's, he said: ``We believe there was some transfer in an unauthorised way of information. We are trying now, many years after the fact, to do an assessment of the damage.''

He, however, said the probe into the alleged leaking of nuclear secrets would not affectnegotiations on China's entry into the World Trade Organisation, adding, ``It would be wrong to try to link these issues.''

``We think it is in our national interest to remain engaged with Beijing on a wide variety of issues including trade... one of the things we have gotten out of this is the lessening of tensions in the Taiwan Straits, which is something very real and tangible,'' he said.

Stating that China's entry into the WTO would be beneficial to Washington, Lockhart said, ``If you look at the situation now, China enjoys much of the WTO benefits as far as access to our market, but American business doesn't enjoy access to the Chinese market that the WTO brings.''

In a related development, US Energy Secretary Bill Richardson, testifying before the Senate armed services committee, said the US believed that ``by engaging China, we have achieved results for we got them to sign the Comprehensive Test Ban Treaty (CTBT) and the Chemical Weapons Convention.

``They have stopped proliferation activitieswith Pakistan and Iran and have also curtailed their missile technology exports around the world -- I won't call it American pressure but through American intervention.''

US special trade negotiator Peter Scher said Washington had not set a deadline for China's admission into the WTO.

``We have not set any deadline... when it's done it's done,'' Scher told mediapersons after testifying before the Senate finance committee subcommittee on international trade.

``To the extent that the Chinese see Premier Zhu (Rongji's) visit as an opportunity to make additional movement and to meet the (WTO entry) requirements, then we view that as a positive thing,'' Scher said.

Other US officials said Zhu's visit here next month would provide China an opportunity to reach a commercially viable deal.