Moscow, Apr 5 (IANS/RIA Novosti): North Korea's recent decision to reinforce its current nuclear weapons capability complicates the prospects of six-party talks on nuclear settlement in the region, the Russian foreign ministry said.

"The prospect of resuming six-party talks to settle the nuclear problem of the Korean Peninsula has been seriously undermined, if not entirely obliterated," ministry spokesman Alexander Lukashevich said.

At a March plenary meeting of the North Korean Workers' Party's Central Committee, North Korean leader Kim Jong-un said the country would adopt relevant laws to maintain its nuclear deterrence forces.

He also said the country would simultaneously build up its nuclear forces and develop its economy.

Lukashevich said Russia is actively consulting all participants of the six-party talks on North Korea's nuclear programme, and that Moscow hopes the sides would return to the negotiating table.

The six-party talks involve North and South Koreas, the US, China, Japan and Russia. The talks have been stalled since 2009.

On Wednesday, the North Korean army said it had received approval to launch a "merciless" attack on the US, including possible nuclear strikes.

The statement followed a pledge by Pyongyang to restart operations at its Yongbyon nuclear complex, including a uranium enrichment plant and a reactor.

Tensions began to rise on the Korean Peninsula after international sanctions were imposed on North Korea in response to a long-range rocket launch in December, which world powers condemned as a ballistic missile test.

North Korea responded by carrying out a third nuclear test in February, which was followed by more sanctions.

North Korea has threatened pre-emptive nuclear strikes against the US mainland and US military bases in the region.

Some of the threats came as US and South Korean forces carried out annual joint military drills, including near the maritime border between the two Koreas. The US responded by deploying F-22 Raptor stealth fighters to the region.