WASHINGTON -- The United States and its allies are prepared to deal with any further provocations by North Korea, US special envoy for North Korea said Wednesday, noting the recalcitrant state may conduct a nuclear test in the future.

Sung Kim also urged the North to return to dialogue, saying the US is prepared to discuss "any concerns" it may have.

"I don't want to speculate too much, but I think it could be another missile launch. It could be a nuclear test," Kim said when asked about the possibility of North Korea conducting a nuclear test around the upcoming anniversary of the birth of its late founding leader Kim Il-sung, which falls on April 15.

"The important thing is that we, in cooperation and coordination with our allies and partners, are prepared to deal with whatever they may undertake. I want to emphasize that we obviously hope that they will refrain from further provocation," he added.

Officials in Seoul and Washington have said the North appeared to be repairing underground tunnels at the Punggye-ri nuclear test site that it had purportedly demolished in 2018 to show its willingness to denuclearize.

Pyongyang has already staged 12 rounds of missile tests this year, while also ending its self-imposed moratorium on long-range missile testing after four and a half years by launching an intercontinental ballistic missile (ICBM) on March 24.

"Hopefully, the anniversary can pass without any further escalation," the US envoy said.

Kim, who concurrently serves as US ambassador to Jakarta, also urged North Korea to quickly return to dialogue, saying the US is prepared to discuss any issues the North wishes to address.

"The DPRK finds itself isolated in unprecedented ways. (It) has shut itself off during the COVID pandemic. Only the resumption of diplomacy can break this isolation, and only then can we pick up the important work that has been done before -- building on the Singapore joint statement," Kim said in a telephonic press briefing, referring to North Korea by its official name, the Democratic People's Republic of Korea.

"We will continue to reach out with a sincere commitment to diplomacy. I sincerely hope this message will make its way to Pyongyang and that they will respond positively," he added.

The Singapore joint statement was issued by former US President Donald Trump and North Korean leader Kim Jong-un in their historic US-North Korea summit held in June 2018, under which the North agreed to denuclearize in exchange for normalized relations with the US.

Kurt Campbell, White House Asia policy coordinator, has said the Joe Biden administration, despite its earlier criticism of Trump's meetings with the North Korean leader, will build on the Singapore statement to denuclearize the Korean Peninsula.

North Korea, however, remains unresponsive to all "public and private messages" from the US, according to Kim.

"We have not received any response from Pyongyang, which is very disappointing because we have sent several messages -- public and private -- inviting them to a dialogue without any conditions," he said. "I still hope that they will respond positively to many outreaches."

"We are willing and prepared to adjust any serious concerns that they may have about the situation on the peninsula," added Kim.

Still, Kim said the US will continue to push for a new UN Security Council resolution on North Korea to hold Pyongyang accountable for its recent missile launches.

"These escalatory and provocative actions by the North Koreans require us to have a decisive response from the (UN) Security Council, and this is why we have in cooperation with partners proposed a new UN Security Council resolution," he said.

The US envoy called on Russia and China to cooperate, noting six US attempts this year to have the UN Security Council issue a public statement against North Korea's missile provocations have failed because of their opposition.

"We believe that the unprecedented number of DPRK ballistic missile launches this year and the instability they bring to the Korean Peninsula are obviously in nobody's interest, and we call on the PRC, as well as Russia, to work with us to send a very clear message through the Security Council that North Korea's actions are unacceptable," he said. (Yonhap)