North Korea pledged to drop its nuclear weapons development and rejoin international arms treaties in a unanimous agreement Monday at six-party arms talks - the first breakthrough in more than two years of negotiations. The North "committed to abandoning all nuclear weapons and existing nuclear programs and returning at an early date" to the Nuclear Nonproliferation Treaty and International Atomic Energy Agency safeguards, according to the agreement. In exchange, the North would receive energy assistance and a pledge from the United States that it won't attack. U.S. Assistant Secretary of State Christopher Hill, the U.S. envoy to the talks, praised the agreement but urged the North Koreans to stop operations at their main nuclear facility at Yongbyon. "It's a good agreement for all of us," Hill said. But he added: "We have to see what comes in the days and weeks ahead. We have to seize the momentum of this." Negotiators agreed to hold more talks in November, where they were expected to move on to concrete discussions about implementing the broad principles outlined in Monday's agreement. Hill has warned that could still be a long process, according to a report of the Associated Press. "The six parties unanimously reaffirmed that the goal of the six-party talks is the verifiable denuclearization of the Korean Peninsula in a peaceful manner," the statement said. North Korea and United States also pledged in the agreement to respect each other's sovereignty and right to peaceful coexistence, and also to take steps to normalize relations. "The United States affirmed that it has no nuclear weapons on the Korean Peninsula and has no intention to attack or invade (North Korea) with nuclear or conventional weapons," according to the statement, in assurances echoed by South Korea. The talks, which began in August 2003, include China, Japan, Russia, the United States and the two Koreas.