The United States has "no good choices" on North Korea but must keep up economic and diplomatic pressure on the secretive regime, former special coordinator Wendy Sherman told lawmakers Wednesday.

"Solving this problem is very, very tough," Sherman told the US Senate Foreign Relations Committee as it weighed her nomination to be the number three at the US State Department. "There are no good choices."

Sherman had been asked what she learned as the special coordinator for North Korea policy from 1997 to 2001 when the United States looked to normalize relations.

"We learned what every administration since has learned: Working with North Korea is very frustrating, exceedingly difficult, they are elusive, they do not keep their commitments, they are often hostile," she said.

Sherman, whose nomination as under secretary of state for political affairs requires US Senate confirmation, noted that US Secretary of State Hillary Clinton had laid out a policy that "it makes no sense to have talks just for the sake of talks."

If North Korea bows to international pressure over its nuclear and missile programs, then it might make sense to have discussions, she said, restating longstanding US policy.

Republican Senator Jim DeMint, pointing to Sherman's record on North Korea, said it "suggests that friendliness and appeasement and trust might be more of your philosophy" with regard to "countries that we know cannot be trusted."

"I am concerned as we approach other countries -- China, Russia, Iran, Syria, the Palestinians -- that these countries respect power and that clarity of purpose is very important for us," he said.

"I don't believe engagement is the antithesis of strength and verification. I believe that engaging with leaders is a way to test them, to see if in fact the commitments they've made, they're going to keep," Sherman replied.

"Sanctions not only remained on North Korea but have increased over the years," she said.