North Korea's top military body also said the denuclearisation of the Korean peninsula would begin when the United States removed nuclear weapons that the isolated state claims it has deployed in the region.
"Dialogue and war cannot co-exist," the North's National Defence Commission said in a statement carried by the official KCNA news agency on Thursday.
"If the United States and the puppet South have the slightest desire to avoid the sledge-hammer blow of our army and the people... and truly wish dialogue and negotiations, they must make the resolute decision," it said, before listing its conditions.
The United States has offered talks, but on the pre-condition that they lead to North Korea abandoning its nuclear weapons ambitions.
North Korea deems its nuclear arms a "treasured sword" and has vowed never to give them up.
Nevertheless, US Secretary of State John Kerry, who ended a trip to the region early this week that was dominated by concern about North Korea, stressed his interest in a diplomatic solution.
South Korea which is conducting military exercises with US forces, to the anger of North Korea, has also proposed talks.
North Korea stepped up its defiance of UN Security Council resolutions in December when it launched a rocket that it said put a scientific satellite in orbit. Critics said the launch was aimed at nurturing the kind of technology needed to deliver a nuclear warhead with a long-range missile.
That was followed in February by its third test of a nuclear weapon. That triggered new UN sanctions in March, sharply toughening existing measures, which in turn led to a dramatic intensification of North Korean threats of nuclear strikes against South Korea and the United States.
"Firstly, the sanctions resolutions by the UN Security Council that were fabricated with unjust reasons must be withdrawn," the North's top military body said in its statement.
"The denuclearisation of the Korean peninsula can begin with the removal of the nuclear war tools dragged in by the US and it can lead to global nuclear disarmament," it added.