SEOUL, Oct 10 (AFP) - North Korea's recent flurry of missile tests were designed to simulate showering the South with tactical nuclear weapons as a warning after large-scale navy drills by South Korean and U.S. forces, state news agency KCNA said on Monday.

North Korea fired two ballistic missiles early on Sunday, officials in Seoul and Tokyo said, making it the seventh such launch since Sept. 25.

Leader Kim Jong Un guided exercises by nuclear tactical operation units over the past two weeks, involving ballistic missiles with mock nuclear warheads, KCNA reported, saying it was to deliver a strong message of war deterrence.

The various tests simulated targeting military command facilities, striking main ports, and neutralising airports in the South, KCNA added.

"The effectiveness and practical combat capability of our nuclear combat force were fully demonstrated as it stands completely ready to hit and destroy targets at any time from any location," KCNA said.

"Even though the enemy continues to talk about dialogue and negotiations, we do not have anything to talk about nor do we feel the need to do so," KCNA quoted Kim as saying.

KCNA said North Korea's ruling Workers' Party decided to conduct the drills as an unavoidable response to a large-scale mobilisation of U.S. and South Korean naval forces, including an aircraft carrier and a nuclear powered submarine.

"The statement they've released is crystal clear that this recent spate of tests was their way of signaling resolve to the United States and South Korea as they carried out military activities of their own," said Ankit Panda of the U.S.-based Carnegie Endowment for International Peace.

The United States and South Korea held joint maritime exercises involving a U.S. aircraft carrier on Friday, a day after the South scrambled fighter jets in reaction to an apparent North Korean aerial bombing drill. read more

The navy exercises involved the U.S. carrier Ronald Reagan and its strike group. The naval forces of South Korea, Japan and the United States also conducted joint drills previous to that.

The U.S.-led UN forces are still technically at war with North Korea as the 1950-1953 Korean war ended in an armistice rather than a peace treaty.