Chinese President Jiang Zemin and Russian President Vladimir Putin yesterday warned the United States of "grave" security consequences if it went ahead with plans to build missile shields.
Capping off a summit dominated by shared suspicions of US motives and global influence, Mr Jiang and Mr Putin put in writing their mutual antipathy to US plans to build anti-missile defences to protect its territory and parts of Asia.
"The plan by the United States to develop a National Missile Defence System (NMD) seeks unilateral military and security advantages," said a joint statement signed by the two leaders.
It said pushing ahead with the plan to protect the US from missiles from hostile regimes would "pose the most grave adverse consequences not only to the national security of Russia, China and other countries, but also to the security and international strategic stability of the United States itself".
China and Russia were "firmly opposed to such a system", which threatened a new arms race, said the statement. Washington has proposed building a NMD system against missile attacks from "states of concern" such as North Korea, Iran and Iraq and a Theatre Missile Defence (TMD) system to shield its troops and allies in Asia.
Missile threats cited by the US as grounds for NMD were "actually a ruse to cover its attempt to violate the ABM", said the Sino-Russian statement, referring to the 1972 Anti-Ballistic Missile treaty.
The document also sharply criticised US plans to build a TMD system in Asia, which China fears includes Taiwan, which it regards as a rebel province.
"The incorporation of Taiwan into any foreign missile defence system is unacceptable and will seriously undermine regional stability," it said.
The joint Chinese-Russian statement comes just after last week's visit to China by the US Defence Secretary, Mr William Cohen, to put back on track military ties frozen after NATO's bombing of the Beijing embassy in Belgrade last year.
Mr Jiang, a Soviet-trained engineer, hailed the pact as an "important success" and said China and Russia would "completely co-operate in the areas of politics, economics, science and technology, military affairs and international affairs".
Despite the statement's clear focus on the US, Mr Jiang said the evolving Beijing-Moscow axis was "a new type of co-operative relationship which is not an alliance, not confrontational and not aimed at any third country".
The US has urged Mr Putin, who flies to North Korea today, to press Pyongyang about its missile programme. China says Washington exaggerates the North Korean missile threat.
After visiting North Korea, Putin heads for the southern Japanese island of Okinawa on Friday evening for the annual gathering of the Group of Eight (G8) nations, which also include the US, Japan, Germany, Britain, France, Italy and Canada.
Meanwhile, the German Chancellor, Mr Gerhard Schroder reiterated Berlin's opposition to the US missile shield plan in an interview published yesterday with Russia's Nezavisimaya Gazeta.
"Germany wants to safeguard the gains in nuclear arms control and disarmament and avoid a fresh arms race," said Mr Schroder.
"Our partners in the EU share this stance," he added.