A senior US diplomat on Sunday urged North Korea to end a recent series of missile tests and resume negotiations, days after the North performed its first underwater-launched ballistic missile launch in two years.

Sung Kim, the top US official on North Korea affairs, spoke after meeting with South Korean officials to discuss North Korea’s recent streak of missile tests that came amid a long-running stalemate in nuclear diplomacy between Washington and Pyongyang.

“We call on the DPRK to cease these provocations and other destabilizing activities, and instead, engage in dialogue,” Kim told reporters, referring to North Korea by its official name, the Democratic People’s Republic of Korea.

“We remain ready to meet with the DPRK without preconditions and we have made clear that the United States harbours no hostile intent towards the DPRK,” he said.

Last Tuesday, North Korea fired a newly developed ballistic missile from a submarine in its fifth round of weapons tests in recent weeks. South Korean officials said the submarine-fired missile appears to be in an early stage of development.

Still, that marked the North’s first underwater-launched test since October in 2019 and the most high-profile one since President Joe Biden took office in January.

Missiles fired from submarines are harder to detect in advance and would provide North Korea with a secondary, retaliatory attack capability.

The launch violates multiple United Nations Security Council resolutions imposed on the North and “poses a threat to the DPRK’s neighbours and the international community,” Kim said.

The Biden administration has repeatedly said it’s ready to meet North Korea “anywhere and at any time” without preconditions. But North Korea says a return to talks is conditional on the U.S. dropping what it calls a hostile policy toward Pyongyang, an apparent reference to U.S.-led sanctions and regular military drills between Washington and Seoul.