By Michelle Nichols

UNITED NATIONS (Reuters) – The United States is making progress in talks with North Korean ally China on imposing new United Nations sanctions on Pyongyang over its latest missile test, but Russia’s engagement will be the “true test,” U.S. Ambassador to the U.N. Nikki Haley said on Tuesday.

The United States gave China a draft resolution nearly three weeks ago to impose stronger sanctions on North Korea over the July 4 missile launch. Haley had been aiming for a vote by the 15-member Security Council within weeks, senior diplomats said.

“We’re constantly in touch with China … Things are moving but it’s still too early to tell how far they’ll move,” Haley told reporters, adding that she was pleased with China’s initial response to the U.S. proposal because it showed “seriousness.”

“We know that China’s been sharing and negotiating with Russia, so as long as they are doing that, we’re going to continue to watch this closely to make sure it is a strong resolution,” she said.

China’s U.N. Ambassador Liu Jieyi told reporters: “We are making progress, it requires time, but we’re working very hard.”

Traditionally, the United States and China have negotiated sanctions on North Korea before formally involving other council members, though diplomats said Washington informally keeps Britain and France in the loop. Along with Russia, those five countries are veto-wielding Security Council members.

“The true test will be what (the Chinese) have worked out with Russia (and whether) Russia comes and tries to pull out of that,” said Haley.

The United States and Russia have waged rival campaigns at the Security Council over the type of ballistic missile fired by North Korea. Western powers have said it was an intercontinental ballistic missile (ICBM), while Russia said the missile fired was only medium-range.

Diplomats say China and Russia only view a long-range missile test or nuclear weapon test as a trigger for further possible U.N. sanctions.

“Everyone that we have dealt with acknowledges that it’s an ICBM. Whether they are willing to put it in writing or not is going to be the real question,” Haley said.

North Korea has been under U.N. sanctions since 2006 over its ballistic missile and nuclear programs and the Security Council has ratcheted up the measures in response to five nuclear weapons tests and two long-range missile launches.

President Donald Trump’s administration has been frustrated that China has not done more to rein in North Korea and senior officials have said Washington could impose new sanctions on Chinese firms doing business with Pyongyang.

When asked how long Washington was willing to negotiate with China at the United Nations before deciding to impose its own secondary sanctions, Haley said: “We’re making progress … We’re going to see what the situation is.”

“We want China and every other country to see it as serious and we’re going to keep moving forward that way,” she said.

China’s Ambassador to Washington Cui Tiankai said on Tuesday that Beijing objected to secondary sanctions. In June, the United States blacklisted two Chinese citizens and a shipping company for helping North Korea’s nuclear and missile programs.

“Such actions are unacceptable. They have severely impaired China-U.S. cooperation on the Korean nuclear issue, and give rise to more questions about the true intention of the U.S.,” he told the Institute for China-America Studies in Washington.

(Additional reporting by David Brunstrom in Washington; Editing by James Dalgleish)