"Although the parties concerned might look at the issue from strategic or political angles, the bid is a business action between companies and fall within normal trade exchanges between China and the United States," Liu said.
"It should not be affected by political issues," Liu added.
US Treasury Secretary John Snow said again on Tuesday that the Bush government will review the takeover deal for national security considerations.
CNOOC, China's largest offshore oil and gas producer, made a bid to Unocal Corp. on June 23, offering to acquire all outstanding shares of Unocal for US$67 per share in cash or a total of US$18.5 billion.
China's energy issue is concerned with its domestic supply and its ability to resolve energy shortages on its own, Liu said in response to a question about China's energy strategy.
When asked to comment on US-DPRK talks, Liu said that China is looking forward to better relations between Washington and Pyongyang.
According to Liu, Pyongyang's presence at an academic conference in New York this week is another sign of a thawing of relations between the two, improving prospects for the restarting of nuclear talks.
Liu said that both the US and the Democratic People's Republic of Korea (DPRK) have signaled their interest in restarting the six-party talks, a move China supports.
"We would like to see the two sides continue to move forward to create more favorable conditions and atmosphere for the talks," he said.
On a less positive note, Liu complained about US interference in China's relations with Israel after reports that the Israeli government had called off an arms deal with China because of pressure from the Americans.
He said cooperation between China and other countries not only brings direct benefits to the parties involved, but also helps to maintain regional stability.
Liu called for the US not to interfere or make irresponsible remarks regarding China's international affairs, to give up its Cold War mentality and to stop creating obstacles between China and other countries.
Meanwhile, a senior US lawmaker has, on Wednesday, reportedly introduced legislation to discourage the European Union from lifting its arms embargo on China.
Moving on, the spokesman expressed China's strong opposition to talks between Japan and Taiwan on fishing issues.
The Chinese government is responsible for the protection of legal rights of fishermen from both the Chinese mainland and Taiwan, Liu said.
He added that there is an existing fishing agreement between China and Japan, and since Taiwan is a part of China, Japan should act in accordance with that agreement.
If there were talks between Japan and Taiwan, Liu said: "It would violate the one-China principle and would not be in accordance with the rules of Sino-Japanese fishing industry agreements."
Liu also expressed unhappiness with Japan, for forcing Chinese fishermen to leave the Diaoyu Islands, a territory to which China lays claim.
Japan and Taiwan reportedly plan to hold talks on their maritime disputes on July 29.
Liu also appealed to Tokyo to put aside their disputes and work on the joint development of oil and gas resources in disputed waters in the East China Sea.
The statement was in response to a report that Japan might approve drilling work in the area by a Japanese company.
Liu said neither side should take unilateral action until the dispute over the boundary is resolved.
He noted that putting aside disputes and pursuing joint development would not only help maintain stability in the East China Sea but also mutually benefit both sides.
On state visits, Grenada's Prime Minister Keith Mitchell will pay an official visit to China from July 7 to 11 at the invitation of Premier Wen Jiabao.
(Xinhua News Agency, China Daily July 1, 2005)
