The US called Sunday on North Korea to act within days on its pledge to halt its nuclear weapons program, while Pyongyang marked the birthday of its late founder with typical pomp and fiery rhetoric. North Korea failed to meet a Saturday deadline to shut down and seal its bomb-making nuclear reactor. US Assistant Secretary of State Christopher Hill said Washington was prepared "to hold on for a few more days" after his Chinese counterpart, Wu Dawei, asked the US for patience during talks in Beijing. "We're not happy that the (North) essentially has missed this very important deadline," Hill told reporters Sunday in Beijing. "We're obviously going to be watching the situation very closely in the coming days." The United States sent a message to North Korea through its embassy in China urging it to fulfill commitments in a February disarmament agreement, which would give the North energy aid and political concessions for disarming. The North said last week it will only move when it receives money from accounts frozen in 2005 after the US blacklisted a bank to pressure the regime, its main precondition for agreeing to disarm. The US$25 million (â‚¬18.6 million) was freed for withdrawal last week after weeks of delay from a bank in the Chinese territory of Macau, but it remains unclear when the North will receive the money. Hill said he expected negotiators from the countries involved in the arms talks - China, Japan, Russia, the US and the two Koreas - would likely meet again before the end of the month to discuss the next steps in disarming North Korea. The North has yet to agree to a deadline for dismantling its nuclear program after the reactor shutdown, which could be easily reversed. No official comment has come from the North since the deadline, with the country consumed Sunday in celebrations of one of its main holidays: the birthday of late founder Kim Il Sung, known as the "Day of the Sun." Kim, father of current leader Kim Jong Il, remains the main focus of an immense personality cult and since his 1994 death, still retains the title as the country's president. On the eve of the holiday Saturday, the North staged a spectacle with thousands of performers in the capital Pyongyang known as the "mass games" - featuring synchronized gymnastics and giant murals formed in the grandstands of an entire side of a stadium by children flipping large books with colored pages. The performance was the first since 2005, after last year's event was canceled because of massive floods that devastated the country, and will continue through May. In one scene, performers danced around a large globe against the backdrop of a giant animated mosaic made by children flipping pages of multicolored books that read, "The sun of the 21st century lights upon us," footage filmed by Associated Press Television News in Pyongyang showed. Kim Jong Il did not attend the show, APTN reported, which also apparently did not include any direct mention hailing the country's newly acquired status as a nuclear power since its first-ever atomic weapons test in October. In an editorial Sunday, the North's main state-run Rodong Sinmun newspaper urged all North Koreans to become "invincible warriors that dedicate our body and mind" to Kim Jong Il, their "destiny and future." North Korean TV footage Sunday monitored in Seoul showed neatly dressed people lined up in front of the 23-meter (75-foot) statue of the elder Kim to pay homage. Officials also visited the palace where the late Kim's embalmed body is enshrined to pay respect "in the most pious manner," the North's official Korean Central News Agency reported.