Israel's deputy foreign minister on Thursday said that a North Korean pledge to suspend nuclear tests in exchange for U.S. aid should not be seen as a model for dealing with Iran's nuclear ambitions.

"The two cases are completely dissimilar," Danny Ayalon told Israeli public radio, hours before Prime Minister Benjamin Netanyahu was due to leave for talks in Washington with U.S. President Barack Obama, expected to center on Israeli concerns that Tehran is racing to produce nuclear arms.

Russia on Thursday welcomed a decision by the new leadership in its neighbor North Korea to suspend nuclear tests and its uranium enrichment program in exchange for U.S. food aid.

"We particularly welcome the decision of North Korea to impose a moratorium on nuclear weapons testing and also on uranium enrichment," the foreign ministry said in a statement.

North Korea's new leadership said Wednesday it would suspend nuclear and missile tests and its uranium enrichment program as part of a deal that includes U.S. food aid for the impoverished nation.

The agreement, confirmed simultaneously by Washington, represents a potential breakthrough in efforts to halt the North's drive for atomic weapons following the death of longtime leader Kim Jong-Il last December.

North Korean leader Kim Jong Un threatened to launch a powerful retaliatory strike against South Korea if provoked, state media said Sunday, a day before the start of annual South Korean-U.S. military drills that Pyongyang calls an invasion rehearsal.

South Korean and U.S. officials have said that the 12-day, largely computer-simulated war games set to start Monday are defensive in nature.

North Korea on Saturday threatened a "sacred war" over U.S.-South Korean joint military drills next week as a U.S. envoy urged Pyongyang's new leadership to engage in dialogue with the outside world.

The North's National Defense Commission (NDC) denounced the annual joint exercises as a "silent declaration of war," describing them as "unpardonable war hysteria."

South Korean troops Monday staged a live-fire artillery exercise near the disputed Yellow Sea border despite threats from North Korea's new leadership of "merciless" retaliation.

The defense ministry said the Marine Corps -- which guards "frontline" islands near the flashpoint border -- began the exercise at about 10 am (0100 GMT) and ended it before noon.

The U.S. and South Korean navies will stage a joint anti-submarine drill in the Yellow Sea next week to guard against potential attacks by North Korea, Seoul's defense ministry said Thursday.

The drill from February 20-24 will involve a number of submarines and warships from both countries, a ministry spokesman told Agence France Presse without elaborating.

The death of North Korean leader Kim Jong-Il raised uncertainty but also opened a window for change in the communist state, South Korea's top official for cross-border ties said Wednesday.

"Chairman Kim Jong-Il's death heightened uncertainties," Unification Minister Yu Woo-Ik said in a speech to a forum.

South Korea staged live-fire drills Thursday from a front-line island shelled by North Korea in 2010, the first such exercise since North Korean leader Kim Jong Il died last month.

Marines at Yeonpyeong Island and nearby Baengnyeong Island fired artillery into waters near the disputed sea border during the two-hour-long drills, a South Korean Defense Ministry official said. The drills were routine exercises and there haven't been any suspicious activities by North Korea's military, the official said on condition of anonymity, citing department rules.

The Associated Press opened its newest bureau in North Korea on Monday, becoming the first international news organization with a full-time presence to cover news in words, pictures and video.

In a ceremony that came less than a month after the death of longtime ruler Kim Jong Il and capped nearly a year of discussions, AP President and CEO Tom Curley and a delegation of top AP editors inaugurated the office, situated inside the headquarters of the state-run Korean Central News Agency in downtown Pyongyang.