UNITED NATIONS (Reuters) - U.S. Secretary of State Rex Tillerson on Friday urged North Korea to carry out a  sustained cessation  of weapons testing to allow the two countries to hold talks about Pyongyang s nuclear and missile programs. Tillerson s remarks were a retreat from his position earlier this week when he offered to begin direct talks with North Korea without preconditions, backing away from a key U.S. demand that Pyongyang must first accept that giving up its nuclear arsenal would be part of any negotiations. But the White House distanced itself from those remarks by Tillerson and said now is not the time for negotiations.  North Korea must earn its way back to the table. The pressure campaign must and will continue until denuclearization is achieved,  Tillerson told a meeting of the United Nations Security Council on North Korea s weapons programs. He did not specify how long the lull should last. He told reporters after the meeting that the United States would not accept any preconditions for talks with North Korea. Tillerson had raised hopes this week that the United States and North Korea could negotiate to resolve their standoff when he said that the United States was  ready to talk any time North Korea would like to talk.  North Korea s ambassador to the United Nations on Friday made no mention of Tillerson s call for a halt to testing when he addressed the same U.N. meeting. Ambassador Ja Song Nam said his country would not pose a threat to any state, as long as its interests were not infringed upon. He described the Security Council session as  a desperate measure plotted by the United States being terrified by the incredible might of our Republic that has successfully achieved the great historic cause of completing the state nuclear force.  North Korea has made clear it has little interest in negotiations with the United States until it has developed the ability to hit the U.S. mainland with a nuclear-tipped missile, something most experts say it has yet to prove.    North Korea conducted missile tests at a steady pace since April, then paused in September after firing a rocket that passed over Japan s Hokkaido island. But it renewed tests in November when it fired a new type of intercontinental ballistic missile, the Hwasong-15, which flew higher and further than previous tests.     Japanese Foreign Minister Taro Kono told the Security Council that North Korea was  nowhere near ready  to abandon its nuclear and missile programs and was not interested in a meaningful dialogue. He said any lull in missile tests did not mean that North Korea was sitting idly.  The latest launch was conducted 75 days after North Korea s provocations in September. Some optimistic views labeled 75 days of silence as a positive signal. However, the missile launch in November made it clear that North Korea was continuing to relentlessly develop its nuclear and missile programs even while they were seemingly silent,  Kono said.                 Tillerson also urged China and Russia on Friday to increase pressure on North Korea by going beyond the implementation of U.N. sanctions, but the two countries were wary of the idea.     China s deputy U.N. ambassador, Wu Haitao, said all parties must implement U.N. sanctions, but said that unilateral sanctions undermine the unity of the Security Council and  hurt the legitimate right and interests of other countries and should therefore be abandoned.  Russian U.N. Ambassador Vassily Nebenzia said Moscow was committed to implementing U.N. sanctions on North Korea and echoed China s concerns about unilateral sanctions.  U.S. President Donald Trump wants China, North Korea s main ally and trading partner, to impose an oil embargo on Pyongyang, over and above Beijing s adherence to U.N. sanctions. The Security Council has ratcheted up sanctions on North Korea over its weapons programs since 2006.            U.N. Secretary-General Antonio Guterres told the Security Council on Friday it was time to immediately re-establish and strengthen communication channels with North Korea, including inter-Korean and military-to-military channels, to reduce the risk of a misunderstanding escalating into conflict. 