By Joyce Lee and Jack Kim SEOUL, Feb 26 (Reuters) - North Korean leader Kim Jong Un said he would focus on expanding his country's nuclear arsenal and that prospects for improving relations with the U.

North Korea has closed out its ruling party’s five-yearly congress with a monumental military parade as leader Kim Jong Un, accompanied by his leather jacket-clad daughter, projected defiance over his nuclear arsenal.

North Korean leader Kim Jong Un has been reelected to the top post of the ruling Workers’ Party, with delegates crediting him for bolstering the country’s nuclear arsenal and strengthening its regional standing.

The North Korean leader, however, took a sterner tone on South Korea, labeling it as a “hostile state and eternal enemy,” and threatening to “completely destroy” it.

Less than a day after the Korean War began, South Korea’s newly acquired patrol ship PC-701 confronted an unidentified vessel off the coast near Busan. The target was a North Korean steam powered freighter carrying hundreds of troops,

The youngster, increasingly viewed as the favorite to succeed Kim, is reportedly being briefed by generals and even giving orders.

A Russian professor specializing in Korean studies and teaching at a South Korean university, Andrey Lankov, was detained by police in Latvia, where he was giving a lecture on North Korea, Russian media has reported.