WASHINGTON • North Korea should not expect rewards from talks with the United States until it takes irreversible steps to give up its nuclear weapons, President Donald Trump's nominee for secretary of state, CIA director Mike Pompeo, has said.

When asked at his Senate confirmation hearing on Thursday if he believed North Korea would agree to dismantle its nuclear programme, Mr Pompeo said historical analysis was "not optimistic". In past negotiations, the US and the world had relaxed sanctions too quickly.

"It is the intention of the President and the administration not to do that this time to make sure that… before we provide rewards, we get the outcome permanently, irreversibly... it is that we hope to achieve," Mr Pompeo said.

"It is a tall order, but I am hopeful that President Trump can achieve that through sound diplomacy," he added.

Mr Trump has said he plans to meet North Korean leader Kim Jong Un in May or early June and hopes the discussions will ultimately lead to an end to North Korea's nuclear weapons programme, which Washington sees as its most pressing security threat.

On Thursday, Mr Trump said meetings were being set up between him and Mr Kim and added that the US would approach the talks respectfully.

He thanked China for its help in trying to resolve the crisis over North Korea's development of nuclear weapons capable of hitting the US.

"They've been really terrific at helping us get to some kind of settlement," Mr Trump said.

"Meetings are being set up right now between myself and Kim Jong Un. I think it will be terrific. I think we'll go in with a lot of respect and we'll see what happens," he said.

Mr Pompeo said he was optimistic a course could be set at the Trump-Kim summit for a diplomatic outcome with North Korea, but added that no one was under any illusion that a comprehensive deal could be reached at that meeting.

He brushed aside concerns that the administration's moves to modify a nuclear deal with Iran could make an agreement with North Korea more difficult.

He argued that Mr Kim would be looking to his own interests, including his country's economy and the"sustainment of his regime", not other historical agreements.

Mr Pompeo stressed that the aim of a Trump-Kim summit was to get North Korea to "step away".

Under questioning, he would not take any option off the table, including military ones.

At the same time, Mr Pompeo said he was not advocating regime change for North Korea and had never done so.

Last year, North Korea accused Mr Pompeo of favouring such a policy after he told a forum in July it was important to separate the country's nuclear weapons from the "character who holds the control over them".

In May, North Korea had accused the CIA and South Korea's intelligence service of a failed plot to assassinate Mr Kim at a military parade in Pyongyang.

On Thursday, Mr Trump's new National Security Adviser, Mr John Bolton, met separately with South Korea's National Security Office director Chung Eui Yong, who led a South Korean delegation that met Mr Kim last month, and his Japanese counterpart Shotaro Yachi.

"The national security advisers committed to continue coordinating closely," a White House official said.

A South Korean diplomat said Mr Chung had a "very useful"meeting with Mr Bolton on preparations for South Korean President Moon Jae In's scheduled April 27 summit with Mr Kim and the planned Trump-Kim meeting, but gave no details.

Mr Bolton, who took up his post on Monday, has called for regime change in North Korea in the past and has previously been rejected as a negotiating partner by Pyongyang.

At a separate congressional hearing, Defence Secretary James Mattis said the aim was for a negotiated solution to the North Korean crisis.

It appears that Pyongyang too does not want anything to spoil the mood for talks. Not a single weapon could be seen depicted among the 80-odd stands at a flower show yesterday to mark the April 15 birthday of North Korea's founder Kim Il Sung. For more than a month the KCNA news agency has barely mentioned the country's nuclear capabilities - in marked contrast to last year's proclamations.

Analyst Robert Carlin wrote in respected US website 38 North that Pyongyang had been "clearly signalling - both in what it has and what it hasn't said - a very different posture than it did last year".

At the same time, he added, "it has begun to open up space for a negotiating position to deal with the issue".

REUTERS, AGENCE FRANCE-PRESSE