Japanese Prime Minister Shinzo Abe concluded a visit to Cuba Friday with condemnation of North Korea's nuclear "provocations" and a request for help from Pyongyang's ally Havana to pursue a "world without nuclear weapons."

Abe, the first Japanese premier to visit Cuba, discussed the nuclear question in meetings with both Fidel and Raul Castro, the brothers who have ruled the communist island since 1959.

"Japan, the only country to suffer a nuclear attack in war, is determined to continue working to achieve a world without nuclear weapons, with the help of Cuba and the rest of the international community," he told a press conference, speaking through a translator.

The comment came after Abe condemned North Korea's recent nuclear weapons tests in his meeting Thursday with President Raul Castro.

"North Korea continues provocations including nuclear tests and the launch of ballistic missiles, which is posing a different level of threat to the region and Japan," he told the president, according to a readout of their conversation from the Japanese Foreign Ministry.

"I know Cuba has had a friendly relationship with North Korea. Having said this, I would point out that the peace and stability of East Asia is crucially important for Japan."

He invited Castro to visit Hiroshima and Nagasaki, the Japanese cities leveled by US atomic bombs at the end of World War II, to witness firsthand the destruction of nuclear weapons.

The Cuban leader said he "strongly wished" to accept the invitation before stepping down in 2018, the Japanese Foreign Ministry said.

Abe also pressed for new efforts on nuclear disarmament in his meeting with former president Fidel Castro, Cuban state media reports said.

Japan said Abe had also asked for the Cuban government's "understanding and cooperation" on the sensitive issue of Japanese citizens believed to have been kidnapped by North Korea to train spies for the reclusive communist state.

North Korea caused outrage in Japan when it admitted in 2002 that it had kidnapped 13 Japanese in the 1970s and 80s to train agents in the country's language and customs.

Five of those were allowed to return home but Pyongyang has insisted, without producing solid evidence, that the eight others died.

- Baseball diplomacy -

Abe arrived in Cuba Thursday, a day after addressing the United Nations General Assembly in New York.

There, he also hammered home Japan's concern over North Korea's test earlier this month of what Pyongyang called a miniaturized nuclear bomb suited to a long-range warhead.

Abe told leaders gathered at the UN that the world has to find "new means" to stop North Korea's nuclear program.

"The threat has now reached a dimension altogether different from what has transpired until now," he said.

Arriving in Havana, Abe said he wants to "open a new page" in Japanese-Cuban relations, after the historic rapprochement between Havana and Washington, Tokyo's close ally.

To that end, he announced a new sports exchange program in which Japan will send coaches to train Cuban baseball players -- a shared passion -- and invite Cuban gymnastics coaches to Japan.

He also broached Japan's call for UN reform, thanking President Castro for his "renewed support" for Tokyo's bid to become a permanent member of the Security Council.

Turning to China -- another Cuban ally with problematic relations with Japan -- Abe told Castro he was "seriously concerned" with Beijing's actions in the East and South China Seas, which include building artificial islands capable of hosting military airbases.