North Korea on Monday called the latest U.N. sanctions "anachronistic and suicidal" and urged the United States to make efforts to ease tensions on the divided peninsula.

A month ago the United Nations Security Council imposed the toughest sanctions in decades over the North's January nuclear test and long-range rocket launch in February.

A spokesman at the North's powerful National Defense Commission said that the international community's "anachronistic and suicidal" sanctions have made Pyongyang even strengthen its will to pursue self-reliance.

Washington's moves for "a war of aggressions against the DPRK to stifle it militarily created the worst crisis in which it may make a retaliatory nuclear strike at the U.S. mainland any moment," the spokesman was quoted as saying by the Korean Central News Agency.

The DPRK stands for the Democratic People's Republic of Korea, the North's official name.

The North has ratcheted up its bellicose rhetoric against Seoul and Washington in recent weeks, threatening to make a "pre-emptive" strike against them.

"The more the U.S. sticks to its show of power against us, the faster it would face a nuclear catastrophe and self-destruction," he said.

The spokesman warned of "the toughest punishment" against the U.S. if Washington passes the threshold by insulting the North's leadership and infringing on the North's sovereign rights.

Also he called on the U.S. to make efforts to bring peace to the Korean Peninsula, saying that pursuing stability and talks, rather than unilateral sanctions and military pressure, will become fundamental solutions for heightened tensions.

Analysts said that North Korea is seeming to try to tip the balance in its favor ahead of its key party congress slated for May.

"The North appears to show that it is ready to have dialogue while claiming that the sanctions have no impact on it," said Yang Moo-jin, a professor at the University of North Korean Studies.

"There is a chance that the North could change its course ahead of the party event."

The North so far has persistently employed saber-rattling tactics.

What appears to be the North's dialogue gesture came amid speculation that Pyongyang may carry out another nuclear or missile test.

North Korea said last month that it plans to conduct nuclear warhead and ballistic missile tests "in a short time," apparently in a show of defiance following tougher U.N. sanctions.

South Korea's defense ministry, meanwhile, flatly rejected the North's offer of talks, saying that now is not the time to discuss dialogue.

"Now is the time to focus on implementing sanctions over North Korea's reckless behavior," Moon Sang-gyun, a ministry spokesman, said in a regular press briefing.

On the effectiveness of the sanctions, the Ministry of Unification said that it is too early to assess the actual impact at the moment. It said more time is needed to collect information such as data on the North's March exports to get a clearer picture of how the sanctions are affecting North Korea. (Yonhap)