UNITED NATIONS (Reuters) - The United States and China are negotiating when they should push for further United Nations Security Council action on North Korea and could reach a decision this week, U.S. Ambassador to the United Nations Nikki Haley said on Tuesday.

North Korean leader Kim Jong Un looks on during a ballistic rocket test-fire through a precision control guidance system in this undated photo released by North Korea's Korean Central News Agency (KCNA) May 30, 2017. KCNA/via REUTERS

Haley characterized the discussions between Washington and Beijing as “at what point ... do we say ‘OK, now it’s time for a resolution?’”

U.N. diplomats, speaking on condition of anonymity, have said it appeared China was still only prepared to act if North Korea conducted a long-range missile launch or a nuclear test and that Beijing does not view the dozens of ballistic missile launches in the past year as warranting further U.N. sanctions.

“(The Chinese) have the lay of the land and so we’re going to keep the pressure on China, but we’re going to continue to work with them in any way that they think is best, and I think that we’ll decide this week on what that looks like,” Haley told reporters.

The Security Council first imposed sanctions on Pyongyang in 2006 over its ballistic missile and nuclear programs and has ratcheted up the measures in response to five nuclear tests and two long-range missile launches. North Korea is threatening a sixth nuclear test.

U.S. Secretary of State Rex Tillerson told the U.N. Security Council on April 28 that the 15-member body needed to act before North Korea does. Just hours after the meeting, chaired by Tillerson, Pyongyang launched yet another ballistic missile.

Within days the United States proposed to China that the Security Council strengthen sanctions on North Korea over its repeated ballistic missile launches. Traditionally, the United States and China have negotiated new sanctions before involving the other 13 council members.

Since then Pyongyang has launched several more ballistic missiles, including a short-range ballistic missile on Monday that landed in the sea off its east coast.

“Nothing is changing North Korea’s actions,” said Haley, adding that it was time to say: “OK, what are we going to do if this is going to happen every other day? How should we respond in a way that we actually stop these things or slow it down?”

Haley said the United States believes “China is doing back-channel networking with North Korea in a way that’s getting them to try and stop the nuclear testing. So we believe that they are being productive.”