Six-party nuclear talks with North Korea failed to deliver their intended results, the State Department said Thursday, adding to Secretary Rex Tillerson's point that diplomatic efforts to disarm Pyongyang failed and a new approach is necessary.

"There's a recognition that certain mechanisms, like the six-party talks, haven't really borne the fruit that we would have liked to have seen them bear over the years," State Department acting spokesman Mark Toner said at a regular briefing.

"That's no surprise to anyone, it hasn't fulfilled its potential," he said.

The Chinese-hosted six-party talks, which also involved the two Koreas, Japan, Russia and the United States, were launched in 2003 to persuade Pyongyang to give up its nuclear programs in exchange for concessions. The negotiating process produced some agreements, but all of them later fell apart as the North backtracked on its promises.

The talks were last held in late 2008.

Earlier Thursday, Tillerson said in Tokyo after talks with his Japanese counterpart that 20 years of diplomatic efforts to end the North's nuclear program have failed, even though the US provided the North with $1.35 billion in assistance, and it's time to come up with a new approach.

Toner said the assistance was provided in food and energy aid between 1995 and 2008.

"All of these past efforts were undertaken with an eye towards finding ways to bring North Korea back into a discussion about its nuclear program and to address concerns about its nuclear program.

But I think given the recent state of missile tests and nuclear tests, that we need to look anew on how we do what we're already doing more effectively with respect to sanctions," Toner said.

"This is a time of real concern. The threat frankly has increased and it's a threat, not just to our allies and partners in the region, but to US national security interests. So with that in mind, we're looking at whatever options we have," he said.

Still, Toner said that the US wants to resolve the standoff "in a way that allows for the peaceful and diplomatic resolution of our concerns" and the US is ready for talks if the North is ready to hold serious denuclearization talks. (Yonhap)