North Korea is expected to feature high at the upcoming Nuclear Security Summit that U.S. President Barack Obama is set to host later this month as part of efforts to make the world free of nuclear weapons, sources said Monday.

In particular, Pyongyang's nuclear pursuit is expected to be the main topic of discussions for a three-way meeting Obama could hold with South Korean President Park Geun-hye and Japanese Prime Minister Shinzo Abe on the sidelines of the nuclear conference, the sources said.

The North Korean nuclear issue won't be adopted as an official agenda item as it isn't directly related to nuclear security. But considering the issue's gravity, it will likely be dealt with in some way during the summit," a source said.

Last week, Amb. Sung Kim, U.S. special representative for North Korea policy, said in an interview with Yonhap News Agency that the North Korea issue could be discussed at the Nuclear Security Summit and at a three-way gathering between Obama, Park and Abe should it take place.

North Korea stunned the world with its fourth nuclear test in January. Pyongyang claimed it carried out a successful test of what it claimed was a hydrogen bomb, through the U.S. said its analysis is not consistent with the North's claims.

A brainchild of Obama, the Nuclear Security Summit is aimed mainly at discussing ways to reduce the stockpile of highly enriched uranium and weapons-grade plutonium, to keep it out of the hands of terrorists and to ensure atomic safety.

The U.S. hosted the inaugural summit in 2010, South Korea the second gathering in 2012 and the Netherlands the third summit in 2014. This month's two-day meeting, set for March 31-April 1, will be the final session of the summit.

Discussions are reportedly under way to set up a trilateral summit between Park, Obama and Abe. The three leaders held a similar three-way summit on the sidelines of the 2014 Nuclear Security Summit at The Hague. (Yonhap)