SEOUL, May 23 -- South Korean Foreign Minister Yun Byung-se and visiting European Union (EU) foreign policy chief Catherine Ashton on Friday reaffirmed that the Democratic People's Republic of Korea (DPRK)'s nuclear weapons program is unacceptable, Seoul's Foreign Ministry said in a statement.

During their meeting, the two diplomats reaffirmed their determined opposition to what they called the DPRK's further provocation, including another nuclear test, agreeing to strengthen cooperation in deterring DPRK provocation and achieving the denuclearized DPRK.

Tensions are running high on the Korean Peninsula as the DPRK threatened a new form of nuclear test after firing some 90 short- range missiles in late February and March. The latest nuclear test of the DPRK was conducted in February 2012.

Pyongyang on Thursday fired two artillery shells in waters near a South Korean naval ship sailing around the disputed maritime border.

Yun and Ashton shared the view that move was very regrettable and intolerable. Ashton pledged to strengthen cooperation with South Korea in tackling the DPRK issues.

After the meeting, the two diplomats singed a basic participatory agreement on crisis management, which covers natural disasters, piracy control and peacekeeping activities.

Ahead of the meeting, Ashton paid a courtesy call to President Park Geun-hye and visited the joint memorial altar in Seoul for the victims of the ferry Sewol disaster, which left more than 300 people, mostly high school students, dead or missing.