The European Union on Thursday beefed up sanctions against North Korea over nuclear and ballistic missile tests carried out in defiance of United Nations resolutions.

The 28-nation bloc said it was adding 18 persons and one entity to its asset freeze and travel ban blacklist, complementing measures adopted by the U.N. against the Democratic People's Republic of Korea, the north's official name.

North Korea has appointed as its new foreign minister a career diplomat at the center of managing relations with the United States and South Korea for more than 20 years.

Ri Yong-Ho's appointment was confirmed in a diplomatic note sent to the British government by the North Korean embassy in London on Monday, an embassy official said.

The State Department has urged Americans to avoid all travel to North Korea, warning that U.S. citizens making the trip risk long and "unduly harsh" imprisonment if they fall foul of laws in the hermit state.

At least 14 U.S. citizens have been detained by Pyongyang over the past decade, according to Washington.

Recent satellite images show no imminent signs of a fifth North Korean nuclear test, following the conclusion of a party congress that many thought Pyongyang would mark with an atomic detonation, a U.S. think tank said Wednesday.

The pictures, dated May 8, show low-level activity at the underground test site at Punggye-ri in the country's northeast, and vehicles previously observed at the site's command centre were "no longer present", according to an analysis by the US-Korea Institute at Johns Hopkins University.

North Korea's former military chief of staff who was reported executed earlier this year is apparently alive and well after being named Tuesday in a number of senior ruling party posts.

Intelligence reports in South Korea had suggested Ri Yong-Gil, former chief of the Korean People's Army (KPA) General Staff, was executed in February on accusations of corruption and forming a political faction.

North Korea held a massive parade in Pyongyang Tuesday, turning the capital's giant square into a sea of pink, to celebrate a ruling party congress seen as a formal coronation for supreme leader Kim Jong-Un.

Kim presided over the event from a balcony overlooking the expansive Kim Il-Sung Square, with tens of thousands of people waving bouquets of artificial flowers over their heads as the young leader arrived.

North Korean strongman Kim Jong-Un cemented control over his ruling Workers' Party on Monday with a new role seen as a coronation for the young leader.

Top U.S .intelligence official James Clapper asked South Korean officials during a recent visit for Seoul's bottom line in any future negotiation between the U.S. and North Korea on a permanent peace treaty, a report said Saturday.

The 1950-53 Korean War ended with an armistice that has never been formalized by a peace treaty, meaning that the two Koreas technically remain at war.

When one of the world's most secretive states opens the door to the international media, it keeps a firm grip on the handle.

Some 130 journalists flocked to North Korea at the express invitation of the Pyongyang authorities to cover the opening on Friday of a rare ruling party congress.

Kim Jong-Un opened North Korea's first ruling party congress for nearly 40 years on Friday, with a defiant defense of the "magnificent" strides made in the country's nuclear weapons program.

Hailing the historic test of what North Korea claims was a hydrogen bomb in January, the isolated state's young leader said it had shown the world it would not be cowed by sanctions or outside pressure.