WASHINGTON (AP) - The United States urged North Korea on May 4 to maintain a moratorium on missile tests.

"The nature of the regime, the conventional forces, the missile exports, the missile developments, all these events in North Korea have been of serious concern to the United States and remain of serious concern," State Department spokesman Richard Boucher said.

"We need to figure out how best to deal with that," he said.

Boucher’s remarks followed a statement by Javier Solana, the European Union’s top security official, that North Korean leader Kim Jong-il views the export of missile technology as a means of earning foreign currency.

The Clinton administration reached an agreement with Pyongyang to freeze its nuclear weapons program in exchange for energy supplies and then aimed for curbs on missile development and exports.

After the Bush administration took over in January it suspended negotiations with North Korea and said it was reviewing U.S. policy. At the same time, the administration cited North Korea’s programs as a major reason for developing a defense against missile attack.

Critics of the suspension argued that continuing negotiations might help reduce the threat.

"We will conduct our review in a thorough manner and we’ll anticipate completing it in a timely fashion," Boucher said May 4.

The State Department spokesman also cautioned North Korea.

"We’ve said before that maintaining the missile launch moratorium is really essential for any future process in our dialogue. If North Korea does maintain this moratorium, that would be constructive," Boucher said.

At the same time, he said the Bush administration supports South Korea in its efforts to ease tensions with North Korea through negotiations.

In fact, Boucher said, the administration favors a second summit meeting between Kim Jong-il and the South Korean President Kim Dae-jung.