UNITED NATIONS >> The United States said today it will push for additional sanctions on North Korea if it conducts a new nuclear test explosion.

U.S., South Korean and Japanese officials have said North Korea could soon conduct its first nuclear test in nearly five years.

On Thursday, China and Russia vetoed a U.N. resolution sponsored by the United States that would have imposed tough new sanctions on North Korea for a spate of launches of intercontinental ballistic missiles that can be used to deliver nuclear warheads. The vote in the 15-member Security Council was 13-2 and marked a first serious division among the five veto-wielding permanent members over a North Korea sanctions resolution.

U.S. Ambassador Linda Thomas-Greenfield was asked today whether the U.S. would seek new sanctions if the North conducted another nuclear test. “We absolutely will,” she said.

A united Security Council imposed sanctions after North Korea’s first nuclear test explosion in 2006 and tightened them over the years in a total of 10 resolutions seeking — so far unsuccessfully — to rein in its nuclear and ballistic missile programs by cutting its sources of revenue.

Last Wednesday, North Korea launched its 17th round of missiles this year, an escalation of weapons tests that experts have said is part of leader Kim Jong Un’s efforts to expand the country’s arsenal and apply more pressure on its rivals to obtain relief from current sanctions and other concessions.

Thomas-Greenfield said the sanctions already in place need to be enforced. And if North Korea tests another nuclear weapon, she added, “We certainly, as we attempted in this last resolution, will push for additional sanctions.”

She was asked about the timing of last Thursday’s vote, since China and Russia’s opposition to new sanctions was well known. They had proposed a resolution easing sanctions on North Korea, and some U.S. allies wanted to try to preserve council unity.

Thomas-Greenfield replied that the U.S. draft resolution had been discussed and considered for nine weeks while North Korea continued to test weapons in violation of Security Council resolutions.

“So, they heard very loudly and clearly that 13 members of the council stand strong in condemning what they are doing and they’re being protected by the Russians and the Chinese veto,” she said. “But now they know that the Russians and the Chinese have not been supported by the members of the council.”

After Thursday’s vote, France’s U.N. ambassador, Nicolas de Riviere, said the Chinese and Russia vetoes amounted “to protecting the North Korean regime and giving it a blank check to proliferate even further.”

“France will continue its efforts to ensure that the council is able to act and that it regains the unity it has had on this issue,” he said.

Under a U.N. General Assembly resolution adopted April 26, the 193-member world body is required for the first time to hold a debate on the situation that sparks a veto in the Security Council within 10 working days. Precedence on the list of speakers is given to the permanent member or members casting the veto.

General Assembly spokesperson Paulina Kubiak said the assembly will hold a meeting on the veto of the North Korea resolution on June 8, but she said she wasn’t in a position to confirm whether China or Russia would participate.