The top nuclear envoys of South Korea and the United States and Japan talked on the phone on Monday to discuss cooperation in responding to North Korea's missile provocations.

According to Seoul's foreign ministry, Special Representative for Korean Peninsula Peace and Security Affairs Kim Gunn spoke with his American counterpart Sung Kim on Monday afternoon.

The phone talks came after the regime fired six short-range ballistic missiles last Thursday and test-fired two strategic cruise missiles from a submarine on Sunday, ahead of Seoul and Washington's joint military exercises that kicked off on Monday. 

The top nuclear envoys reportedly expressed concerns about the missile firing, warning that the provocations will be met with stern responses from the international community including South Korea and the U.S.

The two sides also strongly criticized North Korea for trying to use the joint military exercises and the U.S. Security Council discussions related to North Korean human rights as an excuse to justify their provocations, adding the international community would not tolerate such attempts.

The envoys stressed the importance of the allies' combined exercises in strengthening their ability to respond to North Korea's evolving nuclear and missile threats.