U.S. to 'sharpen' economic pressure on North Korea in aftermath of latest nuclear test

The U.S. will do allit can with financial tools to oppose North Korea's nuclear weapons policy, because co-ordinated economic sanctions have been shownto work, U.S. Treasury Secretary Jack Lew said on Monday.

"I think sanctions have effectively cut North Korea off fromthe global economy," Lew said three days after Pyongyang set offits most powerful nuclear blast to date and claimed to have masteredthe ability to mount a warhead on a ballistic missile.

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"North Korea is an enormous challenge, and we will doeverything we can to keep the pressure on them," he said. "We will continueto sharpen financial tools as we can. The goal is to change the [North Korean nuclear weapons]policy."

He added China'sparticipation is very important.

"We've seen no sign of a change in policy," he said, but the United States is not about to relax sanctions.

South Korea's Defence Ministry warned its neighbour could set off another nuclear test at any time.

"The North is always ready for an additional nuclear test in thePunggye-ri area," the site of the North's five nuclearexplosions so far, South Korean Defence Ministry spokesman MoonSang-gyun told reporters on Monday.

"North Korea has a tunnel where it can conduct an additionalnuclear test," Moon said.

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The South is pushing for more sanctions against Pyongyangto close what it says were loopholes left in the last United Nations Security Council resolution adopted in March.

Both China and Russia backed sanctions imposed in Marchfollowing the North's January nuclear test, but their apparentambivalence about fresh sanctions cast doubt on the SecurityCouncil's ability to form a consensus quickly.

"We expect that China, as one of the Security Council memberstates, should take this issue seriously and play a veryconstructive role to come up with a very effective and strongsanctions resolution," a South Korean foreign ministry officialsaid.

The Security Council denounced the latest test on Friday andsaid it would begin work immediately on a resolution. The UnitedStates, Britain and France three of the five veto-wieldingpermanent members pushed for the 15-member body to impose newsanctions.

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