North Korea appears to be preparing to fire more missiles, a news report said Tuesday, a day after launching a salvo in what could be an attempt to improve its bargaining position ahead of possible talks with the United States. North Korea test-fired five short-range ballistic missiles into its eastern waters Monday - the regime's first missile launches since early July. The latest launches came as Washington considers whether to accept Pyongyang's proposal for direct talks. The communist nation is preparing to fire more short-range missiles off its west coast and has announced a no-sail zone there, Seoul's Yonhap news agency said, citing an unidentified government official. South Korea's YTN television network carried a similar report saying North Korea had announced a no-sail zone in areas off the country's east and west coasts for Oct. 10-20 - an apparent indication the country could carry out more missile tests. Officials at the Defense Ministry and the presidential Blue House declined to confirm the reports. North Korea has recently reached out to the US and South Korea following months of tension over its nuclear and missile tests earlier this year. Leader Kim Jong Il told visiting Chinese Premier Wen Jiabao last week that his government might return to stalled six-nation negotiations on its nuclear program depending on the outcome of direct talks it seeks with the US. Washington has said it is considering holding direct talks with North Korea to restart the six-party negotiations, which also include South Korea, Japan, China and Russia. South Korea's Foreign Ministry spokesman Moon Tae-young denounced the latest launches as violation of UN Security Council resolutions banning North Korea from any ballistic missile-related activity. Officials refused to identify the types of missiles launched Monday. But Yonhap said the KN-02 surface-to-surface missiles were fired from mobile launch pads and had a range of up to 120 kilometers. It said North Korea launched two missiles in the morning and three more in the afternoon. US Secretary of State Hillary Rodham Clinton said in Belfast on Monday that American efforts to resume the nuclear talks with North Korea will proceed despite the new tests. "Our goal remains the same," she told reporters after a meeting with Northern Irish business leaders. "Our consultations with our partners and our allies continues unabated. It is unaffected by the behavior of North Korea." Clinton was to fly later to Moscow to meet with Russian leaders on a variety of issues, including nuclear reduction concerns. Monday's launches appeared to be aimed at displaying North Korea's missile capability to bolster its negotiating hand ahead of talks with the US and other countries to wrest more concessions, said Koh Yu-hwan, a North Korea expert at Seoul's Dongguk University. Yang Moo-jin, a professor at Seoul's University of North Korean Studies, agreed and added that North Korea was unlikely to take more drastic steps such as its April long-range rocket test or May nuclear test. About 200 demonstrators gathered in central Seoul on Tuesday to denounce the North's missile launches. Some burned North Korean flags and photos of North Korean leader Kim Jong Il. Meanwhile, North Korea agreed to hold two sets of working-level talks with South Korea, Unification Ministry spokeswoman Lee Jong-joo said Tuesday, a day after Seoul proposed the talks. Officials from the two sides plan to meet Wednesday at a North Korean border city to discuss how to prevent Imjin River flooding from running through their heavily armed border, Lee said. She also said Red Cross societies of the two sides planned to hold talks Friday to discuss reunions of families separated by the 1950-53 Korean War. Ties between the two Koreas soured after conservative South Korean President Lee Myung-bak took office early last year with a pledge to get tough with the North's government. Tensions further heightened after North Korea conducted its long-range rocket and nuclear tests. The Korean War ended in a cease-fire, not a peace treaty, which means the two Koreas are still technically at war.