The White House on Thursday imposed economic sanctions on five Chinese firms and a North Korean company that it said had assisted Iran's weapons programs. It did so even as US officials were meeting with a senior Chinese diplomat, trying to coax Beijing into forcing North Korea to dismantle its nuclear program.
The administration's mixed signals underscored the difficulties it faces in pursuing an aggressive agenda of counter-proliferation.
It is publicly praising China in an effort to persuade it to put pressure on North Korea and Iran to dismantle their nuclear programs, while quietly protesting that Chinese companies are a major source of technology.
Three of the four Chinese firms named on Thursday are already under sanction for their role in the arms trade.
"It shows you how far we have to go to get the basic technology cut off," one senior administration official said. "In China, in Pakistan, in Russia, you get government cooperation, and then you discover all the side deals that companies have made with rogue states."
At the State Department on Thursday, Richard Boucher, the spokesman, told reporters that the sanctions, which were quietly announced in the Federal Register on Thursday morning, were "not done in any manner to coincide with a visit" by China's deputy foreign minister, Wang Yi.
US and Asian officials said that the Chinese intended to use Thursday's visit to urge the US to meet again with North Korea, with only China as a participant and intermediary in the talks.
So far, North Korea has refused to allow South Korea and Japan to join the talks, as US President George W. Bush has insisted. The first meeting, in April ended badly, with North Korea declaring it had nuclear weapons and might sell them.
It is unclear if the economic sanctions imposed on Thursday will affect Beijing's cooperation with Washington.
But the practical effects of the sanctions will be minimal: Most of the companies named by the State Department do no business with the US government because of existing sanctions against them.
Still, Bush and his aides are clearly signaling an intent to move forward aggressively with a broad new strategy to cut off aid to the North Korean and Iranian weapons programs. They have described a new approach that calls for the use of domestic law-enforcement agencies in ports in Japan, Singapore and in Europe to stop and search ships suspected of carrying missiles or nuclear technology.
The State Department offered no details of the shipments to Iran that prompted the latest round of sanctions. The announcement said simply that the shipments had, "the potential to make a material contribution to weapons of mass destruction or missiles."
The sanctions were imposed against four Chinese firms: the Taian Foreign Trade General Corp, the Zibo Chemical Equipment Plant, the Liyang Yunlong Chemical Equipment Group Co of China and one of the largest companies in the Chinese military complex, China North Industries Corp, better known as Norinco.
Norinco, a major supplier to the Chinese military that does billions of dollars of business in China and overseas, has previously been charged in smuggling cases in the US, and has been accused of supplying many nations with banned military hardware.
The North Korean firm, Changgwang Sinyong Corp, has long been linked to North Korean missile sales and was identified earlier this year as the company involved in a barter arrangement between Pakistan and North Korea.