Amid growing media speculation that the resumption of nuclear talks with North Korea may be in the offing, top South Korean and U.S. officials had a four-hour meeting here Monday aimed at "fine-tuning" a strategy on North Korea demanding dialogue without pre-conditions attached.

 Cho Tae-yong, Seoul's special representative for Korean Peninsula peace and security, said he had "very productive and useful" discussions with his American counterpart Glyn Davies.

"We reaffirmed that our line of thinking are in sync and consistent with each other," Cho told reporters, stepping out of the State Department together with Davies.

He added, "Based upon the common thinking, we are in the process of fine-tuning our thoughts."

Davies also said he and Cho talked about "all aspects of the North Korea issue."

"This is part of an intensive series of discussions that we have had in recent weeks," he added.

Cho arrived in Washington on Sunday. He plans to hold a trilateral session with Davies and Japan's chief nuclear envoy, Junichi Ihara, on Tuesday.

The meetings coincide with a surprise visit to Pyongyang by China's top point man on Korea, Wu Dawei, who traveled to Washington last week.

China has been active in efforts to revive the six-party talks last held in December 2008. Russia is another participant.

Such back-to-back diplomatic activities among the relevant parties have spawned speculation on possible progress.

Pyongyang, staging months of a charm offensive, has called for any type of dialogue without attaching any pre-conditions.

But Washington has reiterated that the secretive communist nation should first take steps to prove its seriousness on denuclearrization.

A South Korean government official cautioned against excessive optimism, comparing the ongoing diplomatic process to birth pangs.

"Media may expect an imminent, smooth birth. But we are not there yet. We are going through labor pains, of which the ending time is hard to predict," the official said on the condition of anonymity.

Diplomatic sources also say despite brisk consultations on the terms for restarting the six-way talks, the Obama administration is not yet ready to make any decision. (Yonhap News)