UNITED NATIONS/WASHINGTON (Reuters) - The United States has given China a draft resolution for tougher U.N. sanctions on North Korea and is hoping for a quick vote on it by the U.N. Security Council, a Western diplomat said on Tuesday.

A senior official of the Trump administration confirmed efforts were under way to negotiate a new U.N. resolution, but added that there had been no agreement.

“We’re trying to get another one,” said the official, who did not want to be identified. “They’re not there yet.”

Details of the draft given to China last week were not immediately available, but the United States is keen to step up global sanctions to pressure North Korea to give up a weapons program aimed developing nuclear-tipped missiles capable of hitting the United States.

Among the steps it wants is a tightening of restrictions on North Korea’s supply of refined petroleum, which is capped by previous U.N. sanctions at 2 million barrels a year.

China, which supplies most of North Korea’s oil, has backed successive rounds of U.N. sanctions but has resisted past U.S. calls to cut off supplies to its neighbor. Its embassy in Washington and Foreign Ministry in Beijing did not immediately respond to a request for comment.

The United States has also called on the U.N. Security Council to blacklist 10 ships for circumventing sanctions on North Korea, documents seen by Reuters on Tuesday showed.

The documents said vessels had been conducting ship-to-ship transfers of refined petroleum products to North Korean vessels or transporting North Korean coal in violation of existing U.N. sanctions.

Earlier on Tuesday, China responded to the announcement of a new U.S. national security strategy this week that branded Beijing a competitor seeking to challenge U.S. power by saying that cooperation between it and Washington would lead to a win-win outcome for both sides, but confrontation would bring mutual losses.