Chinese Foreign Ministry spokesman said Monday that US statements to date in the plane standoff have been "unacceptable", again demanding a full US apology for the collision of a US spy plane with a Chinese fighter jet.

Zhu said a Chinese investigation into the events April 1 is proceeding in accordance with international and Chinese law. When asked when the crew might be released, he said one important factor would be the ``results'' obtained from that investigation.

China has said it is holding the 24 US crewmembers in ``protective custody.''

``The United States should apologize and respond appropriately. If they don't, it's going to make things difficult. If they do, it's going to help resolve the problem,'' said Zhu Bangzao, a senior Chinese foreign ministry official, speaking at a news conference in Argentina.

Speaking amid Jiang's visit to Argentina, the senior Chinese foreign ministry official said his country remains unsatisfied by the U.S. response since the April 1 collision of a Chinese fighter jet with a U.S. spy plane over the South China Sea.

``Where is the responsibility? I think it's very clear,'' said Zhu, who was peppered by questions at the only formal news briefing. ``The pronouncements of the United States are unacceptable to the Chinese people.''

Zhu, speaking through a translator, suggested recent US statements did not go far enough. Jiang said last Thursday in Chile, where he kicked off a 12-day tour of Latin America, that he still wanted a US apology demanded earlier.

Zhu did not state publicly why Chinese officials think the American response was inadequate. Nor would he elaborate on any specific statements made recently by US Secretary State Colin Powell or others in the administration of US President Bush.

Over the weekend, Powell had said the US government was ``sorry'' for the Chinese fighter pilot still missing and feared dead. On April 5, Bush also offered his personal regrets at the apparent loss of life but the US government has stopped short of apologizing.

Zhu repeated Chinese government assertions that the American plane violated Chinese airspace during its surveillance flight off the south Chinese coast. ``It was the American plane that entered our airspace,'' he said, insisting the surveillance plane landed without permission on Chinese territory. ``We have all the evidence.''

Earlier Monday, Bush said in Washington that diplomacy does take time, but warned that the potential for damage to the relationship rises ``Every day that goes by'' without a resolution.

Jiang, who is on an extensive trip of five South American countries and Cuba, did not make any commment Monday on the spy plane standoff, leaving the foreign ministry official to respond to questions.

But last Thursday in Chile, Jiang repeated Chinese demands that the United States apologize.

(Agencies 04/10/2001)