Worries that North Korea would conduct a second nuclear test kept nerves on edge on Wednesday (October 11) as Japan, facing Chinese and Russian reservations about the scope of UN sanctions pressed for a stern response to Pyongyang. In the North Korean capital, the reclusive communist state's No. 2 leader said that whether his country conducted more tests depended on Washington. The Japanese government has denied it had information indicating that North Korea had conducted a second nuclear test. Japanese public broadcaster NHK reported early on Wednesday that North Korea appeared to have conducted another nuclear test. NHK said Japanese government sources had information that there was a tremor in North Korea this morning and they were checking on the possibility of a nuclear test. However Land Transport minister Tetsuzo Fuyushiba told parliament that Japanese seismic analysis had detected no tell-tale signs of a nuclear test in North Korea. Japan said it had detected no seismic waves in North Korea on Wednesday between 5:00 a.m. and 8:30 a.m. (2000 GMT-2330 GMT Tuesday). "We checked data thoroughly, but we detected no seismic waves," Land Minister Tetsuzo Fuyushiba told a parliamentary committee. North Korea announced on Monday that it had conducted its first-ever nuclear test, defying warnings from its neighbours, the United States and the U.N. Security Council. Pyongyang had said earlier a U.S. "threat of nuclear war and sanctions" had forced its hand. There was however a quake of magnitude 6.0 by Japan measurement standards at 8:58 a.m. (2358 GMT) in the ocean northeast of Tokyo that some officials say may have been the source of the confusion. Nevertheless, Japan remains staunchly looking at North Korean sanctions in the face of what it calls a grave provocation. "If North Korea has indeed conducted nuclear tests then that would greatly change the face of peace and security in North East Asia and the Far East. I think we have entered another very dangerous nuclear age," Japanese Prime minister Shinzo Abe told parliament. Japan imposed a first round of sanctions in July after North Korea carried out a flurry of missile tests, and an overwhelming majority of Japanese support further measures, a poll released on Tuesday showed. Eighty-three percent of respondents in a Kyodo news agency survey said economic sanctions should be further stepped up. In the streets of Tokyo, the reports of a possible second test were greeted with increased outrage. "We can do nothing about such a hopelessly insecure country alone no matter how strong we react unless the international community acts through the United Nations, " Minoru Mochida, a 42 year-old company employee. "It's very scary. They might do it again. I'm afraid to go outside," said a younger 24 year old Tomoko Okawa. China and Russia, which both border North Korea, met other veto-holding members of the U.N. Security Council on Tuesday (October 11) to discuss a range of sanctions proposed by the United States and Japan to pressure Pyongyang to abandon its nuclear programme. South Korea said on Wednesday (October 11) that the country will only focus on specific sanctions after the Security Council's decision. "Of course in the process we will be examining the situation and prepare measures, but that will be after the resolution is finalised," South Korean Vice Foreign Minister, Lee Kyu-Hyung said. 430 tonnes of rice in aid for North Korea has been sitting in Ulsan. The South Korean Red Cross was planning on sending 5,000 tonnes of rice to North Korea by Oct 13 and that is also on hold now. A North Korean official stationed in Beijing told the South Korean Yonhap news agency a strict sanctions regime would be tantamount to war. There has been a lot of speculation of the type of nuclear test the isolated regime conducted. "I think it was a nuclear test, even though it might not explode as they had planned. That is a probable consequence if it was a plutonium bomb," said Kumao Kaneko, President of Japan Council on energy and Security. He added that the nation has now entered a stage where they need to focus on accuracy--so in that aspect, this might be a success, he added.