South Korea and Washington stand firm on their stance on North Korea's denuclearization process, reiterating that North Korea should first comply with a preemptive measure demanded by South Korea and the United States before the communist country can enjoy economic assistance again.

In the opening day of the United Nations General Assembly, South Korean president, Lee Myung-bak said North Korea must relinquish its nuclear ambitions before its neighbor South Korea was willing to help the impoverished communist country.

"It is my hope to see the DPRK enjoy peace and prosperity by becoming a responsible member of the international community. When the DPRK chooses the path to a mutual benefit and common prosperity, we will be ready to help in this endeavor along with the international community," reports the Yonhap News Agency as President Lee spoke before the delegates of the General Assembly.

"The North Korean nuclear threat poses significant challenges to peace on the Korean Peninsula, Northeast Asia and beyond," the South Korean president continued.

Lee's speech came up after peace talks in Beijing failed to come up with a mutual agreement on the preemptive measure, a requisite that could have opened up the six-party denuclearization negotiation again. North Korea's strongman Kim Jong-il asserted the nuclear peace talks should take place without strings attached.

The South Korean leader urges the international community to combat nuclear terrorism and the prevalence of weapons of mass destruction like biological and chemical weapons and long-range missiles.

"The greatest threat of all perhaps emanates from nuclear terrorism. International cooperation is now needed more than ever to prevent nuclear terrorism," President Lee said reiterating that in a Nuclear Summit in Seoul next year, the war against nuclear terrorism is on the agenda.

Meanwhile, U.S. President Barack Obama announced in his speech at the U.N. General Meeting that North Korea will suffer greater pressure and isolation should it decide to pursue its nuclear endeavors and adverse dealings with South Korea.

"North Korea has yet to take concrete steps towards abandoning its weapons, and continues belligerent actions against the South. If they continue down a path that is outside the international law, they must be met with greater pressure and isolation. That is what our commitment to peace and security demands," President Obama said.