U.S. Ambassador John Bolton was confident Thursday of "growing support" in the United Nations Security Council to pass a resolution that would impose a travel ban and financial sanctions against North Korea in response to its claimed nuclear test.

After a morning session with Security Council members, Bolton said he saw no reason why the council could not vote on the resolution on Friday.

"I think that the council should try to respond to a nuclear test the same week the test occurred," Bolton told reporters. "We're certainly in favor of keeping all the diplomatic channels open, but we also want swift action, and we shouldn't allow meetings, and more meetings ... to be an excuse for inaction."

Russia, meanwhile, urged the United States not to rush the vote, saying Moscow still had differences and the U.S. should wait for the results of a flurry of high-level diplomacy. China backed Russia's call, saying Beijing would welcome more talks so the Security Council can send a united and forceful message to Pyongyang condemning the reported test.

Earlier Thursday, China expressed regret that a draft resolution circulated by the U.S. focused on punitive measures without providing incentives to draw Pyongyang back to the negotiating table.

North Korea should understand it had made a mistake, but "punishment should not be the purpose" of any U.N. response, said Liu Jianchao, a spokesman for the Chinese Foreign Ministry in Beijing.

U.N. action "should be conducive to the de-nuclearization of the Korean peninsula ... and the resumption of the talks," he said. "It's necessary to express clearly to North Korea that ... the international community is opposed to this nuclear test."

Diplomatic efforts to reach an agreement extended to the White House, where President Bush met Thursday with a special envoy of China President Hu Jintao.

China's State Councilor Tang Jiaxuan assured Bush that Beijing is seeking a strong U.N. response to North Korea, but that it only wants sanctions related to the country's weapons program, White House spokesman Frederick Jones said.

Tang also met with Secretary of State Condoleezza Rice and White House national security adviser Stephen Hadley.

Rice described the talks as "excellent," saying that the Chinese "understand the gravity of the situation."

CountryWatch: North Korea

China's response to the crisis has been closely watched because it is considered to have the most leverage with the unpredictable, reclusive North Korean regime. China, a veto-wielding Security Council member, is the North's top provider of desperately needed energy and economic aid.

Chinese officials have refused to say publicly what consequences they believe North Korea should face for its claimed nuclear test, although its U.N. ambassador, Wang Guangya, agreed earlier this week that the Security Council must impose "punitive actions."

In China, the foreign ministry said China and the United States were discussing a possible visit to Beijing by Rice.

Japan, meanwhile, moved Thursday to impose its own new sanctions against North Korea. The ruling Liberal Democratic Party approved several harsh measures, including limits on imports and a ban on all North Korean ships in Japanese waters.

The latest U.S. proposal, obtained by The Associated Press Wednesday night, dropped Japanese demands to prohibit North Koreans ships from entering any port, and North Korean aircraft from taking off or landing in any country. These sanctions would likely face strong Russian and Chinese opposition.

The resolution would still require countries to freeze all assets related to North Korea's weapons and missile programs. But a call to freeze assets from other illicit activities such as "counterfeiting, money-laundering or narcotics" was dropped. So was a call to prevent "any abuses of the international financial system" that could contribute to the transfer or development of banned weapons.

North Korea, meanwhile, warned it would consider increased U.S. pressure an act of war and take unspecified countermeasures.

The North will consider increased U.S. pressure "a declaration of war," RI Kong Son, vice spokesman for North Korea's Foreign Ministry, said in an interview with AP Television News in Pyongyang. He said North Korea would take unspecified "physical countermeasures."

Song Il Ho, a North Korean envoy to Japan, gave a similar warning to Tokyo. "We will take strong countermeasures," he told Kyoto News Agency.

Since Pyongyang announced it exploded its first atomic bomb Monday, there have been daily South Korean and Japanese news reports that the North is preparing another test.

On Thursday, the South Korean newspaper Munhwa Ilbo quoted an unidentified source familiar with North Korean affairs as saying a second test would occur in two or three days.

South Korea's National Intelligence Service could not immediately be reached for comment.

Click here to go to FOXNews.com's North Korea Center.

South Korean scientists have been scrambling for signs of radioactivity that would confirm Monday's underground test. Han Seung-jae, an official at the Korea Institute of Nuclear Safety, said experts were still unsure the North had tested a nuclear device.

"So far, we have not detected any abnormal level of radioactivity" in South Korea, he said.

Japanese military planes have also been monitoring for radioactivity in the atmosphere but have reported no abnormal readings.

North Korea has been demanding direct talks with the United States, but President Bush refused to agree to such a meeting in a news conference Wednesday. He argued that Pyongyang would be more likely to listen to the protests of many nations.

Bush added that the U.S. was ready to defend its allies in the region, but that it would also try to use diplomacy to deal with North Korea.

"I believe the commander in chief must try all diplomatic measures before we commit our military," he said.

The Associated Press contributed to this report.