China intends to modernize its nuclear and other military forces whether or not the United States follows through with development of a defense against long-range missiles, a Chinese diplomat said Wednesday.

Upgrading China's forces is a natural development along with growth of the Chinese economy, the official said. They go hand-in-hand, he told reporters at the Chinese Embassy.

China will hold to its pledge under the international test ban treaty not to conduct a nuclear weapons test explosion, he said.

But there are other ways, in the laboratories and using computers, to improve China's missile arsenal, said the official, speaking on condition of anonymity.

On Capitol Hill, Secretary of Defense Donald H. Rumsfeld said the Bush administration does not intend to approve or condone a buildup of China's nuclear forces.

Rumsfeld disputed news reports the administration would tacitly accept such a buildup.

"The suggestion that the United States has or is poised to approve of China's military and nuclear buildup for some reason in exchange for something is simply not the case, notwithstanding what people are reading in the press," Rumsfeld told a Senate appropriations subcommittee.

Meanwhile, a senior U.S. official told The Associated Press that China's forces were slated for expansion and modernization long before the Bush administration came on the scene and began talking about missile defenses.

The primary concern is whether China intends to step up development of medium-range and long-range missiles, the official said. China is far behind in both areas, but it is not barred from developing intermediate-range missiles as the United States and Russia are by treaty, the official said, speaking on condition of anonymity.

The official said the United States can do nothing to prevent China from modernizing its strategic forces, but the Bush administration would not sit idly by if it did.

For one thing, he said, the administration intends to enforce stringently an agreement reached with China last November to curb the spread of missile technology.

The official also disputed newspaper reports that the United States will signal China it recognizes that both sides want to resume nuclear weapons tests.

The Senate has refused to ratify the test ban treaty, but the Bush administration has extended the President Clinton's moratorium on testing.

Last week, the administration accused the China Metallurgical Equipment Corp., a government-owned engineering company, of supplying missile-related parts to Pakistan.

For two years, the company will be denied all new U.S. licenses for production of electronics and military equipment and for material used to launch commercial satellites.

On Wednesday in Beijing, and also at the Chinese Embassy, the U.S. allegation was denied. The company did not ship material to Pakistan in violation of the agreement, the Chinese official said, and China has asked the Bush administration for evidence.

In saying China will proceed with modernizing its nuclear arsenal, the official said it was not designed as a threat against any country.

At the same time, he registered his government's objections to a U.S. anti-missile system, saying it would upset the strategic balance of the last half-century and would touch off a nuclear arms race.

The Bush administration has based its pursuit of a shield on claims North Korea, Iraq, Iran and possibly other countries could threaten the United States with long-range missiles.

The Chinese official said the threat from North Korea is either exaggerated or imagined.