The US secretary of state, John Kerry, has said North Korea has “not even come close” to taking the steps needed to rein in its nuclear weapons programme to initiate talks, adding the US was considering further sanctions.

Speaking in the South Korean capital, Kerry said Washington continued to offer North Korea the chance for an improved relationship in return for signs of a genuine willingness to end its nuclear programme.

“To date, to this moment, particularly with recent provocations, it is clear the DPRK [Democratic People’s Republic of Korea] is not even close to meeting that standard,” Kerry told a joint news conference with the South Korean foreign minister, Yun Byung-se. “Instead it continues to pursue nuclear weapons and ballistic missiles.”

North Korea is already under heavy US and UN sanctions for its missile and nuclear tests but Kerry said further penalties were being considered.

He said it was likely North Korea would be referred to the international criminal court if its behaviour on human rights continued.

In 2005, Pyongyang walked away from a deal with the US, Russia, South Koreaand China to end its nuclear programme in return for diplomatic and economic rewards.

It recently tested what it said was a submarine-launched ballistic missile, raising regional tensions about the prospect of a heightened threat that already includes nuclear arms development and an arsenal of ballistic missiles.

North Korea is technically still at war with the South after the 1950-53 conflict ended in a truce, not a peace treaty, and regularly threatens to destroy the South’s major ally, the US.