North Korea pledged Wednesday not to lay down its nuclear weapons as it called on South Korea to stop annual joint military drills with the United States. The North vowed last year to develop its economy and nuclear arsenal in tandem, a dual-track policy South Korea and the U.S. have warned is a dead end for the communist country. The North has called its nuclear programs a "treasured sword" against what it claims is Washington's policy of hostility. South Korea "should not even dream that we will be coaxed into laying down our nuclear" programs by sweet talk, the North's Committee for the Peaceful Reunification of Korea said in comments carried by the country's official Korean Central News Agency. The committee, which handles inter-Korean affairs, was referring to South Korean President Park Geun-hye's initiative toward North Korea. Park called for the bolstering of exchanges with the North as a first step toward building trust between the sides to lay the groundwork for unification of the two Koreas. She unveiled the proposal, called the Dresden Declaration, during her trip to the former East German city of Dresden last month. The committee's comments came as North Korea has increased movements of vehicles and troops at its main nuclear test site, an possible indication that Pyongyang will conduct another nuclear test as U.S. President Barack Obama visits Asia. North Korea conducted nuclear tests in 2006, 2009 and February 2013, drawing international condemnation and tougher U.N. sanctions. The North has threatened to carry out a "new form" of nuclear test in anger over the U.N.'s condemnation of its ballistic missile launches into the sea off its east coast. The committee pressed South Korea to halt its annual military drills with the U.S., which Pyongyang condemns as a rehearsal for invasion. It also called on South Korea to lift its sanctions imposed on Pyongyang nearly four years ago. Those economic sanctions were imposed on the North in May 2010 in retaliation for the sinking of a warship near their disputed western sea border in March that year that killed 46 South Korean sailors. Under the sanctions, South Korea has suspended inter-Korean projects and banned new investment in the North, except for their joint factory park in the North's western city of Kaesong. South Korea has called for, among other things, the North's admission of its involvement in the sinking in return for lifting the sanctions, though Pyongyang has refused to take responsibility for the deadly attack. The North's committee asked if Park is willing to carry out agreements reached at two previous inter-Korean summits in 2000 and 2007. The first summit paved the way for the two Koreas to ease military tensions and begin economic cooperation after decades of hostilities. In 2007, the leaders of the two Koreas produced a deal calling for massive South Korean investment in the North's key industrial sectors, including shipbuilding. The deals have been in limbo as tensions persist on the divided peninsula over the North's missile and nuclear programs. Inter-Korean relations "depend on Park's attitude," the committee said.