SEOUL, May 27 -- Top negotiators of South Korea, the United Statesand Japan, who represent each of their countries in the six-party talks to denuclearize the Korean Peninsula, have discussed ways of returning the Democratic People's Republic of Korea (DPRK) to the dialogue table for its nuclear program.

The three nuclear envoys held the trilateral meeting in Seoul for two days through Wednesday, discussing how to deter possible DPRK provocations and make effective the sanctions imposed by UN Security Council banning the DPRK from developing the nuclear program and test-firing ballistic missiles.

The chief negotiators included Hwang Joon-kook, South Korea's special representative for Korean Peninsula peace and security affairs as well as Sung Kim, U.S. special representative for DPRK policy and Junichi Ihara, Japanese foreign ministry's director- general for the Asian and Oceanian Affairs Bureau.

"The three nations shared a view of seriousness in North Korea (DPRK)'s enhanced nuclear capability," Hwang told reporters after the meeting. "(The three parties) agreed to continue efforts at both strong pressures on and active dialogue with North Korea ( DPRK)," said Hwang.

The longer the DPRK refrains from returning to the dialogue table, the stronger international pressures would be, and it would deepen the DPRK's diplomatic isolation, Hwang said, urging Pyongyang to come back to the six-way dialogue.

The aid-for-disarmament talks, involving South Korea, the DPRK, China, the United States, Russiaand Japan, were initiated in August 2003 but have stalled since December 2008.

Sung Kim, the chief U.S. negotiator, told reporters that the three countries agreed to the importance of stronger pressures and sanctions toward the DPRK, indicating the U.S. considering UN- level actions.

U.S. Secretary of State John Kerry, who visited Seoul for two days to last Monday, hinted at additional sanctions on the DPRK for the submarine-launched ballistic missile during his stay.

Tensions escalated on the Korean Peninsula after the DPRK said on May 9 that it had successfully test-fired a submarine-launched ballistic missile.

The DPRK's National Defence Commission last Wednesday said that it had a capability of miniaturizing and diversifying nuclear warheads to mount them onto ballistic missiles.