South Korea and the United States are expected to adopt a document on comprehensive cyber security cooperation and seek expanded information sharing during a leaders' summit set for April 26 in Washington.

According to a high-ranking official who met with South Korean reporters in Washington on Thursday, the document could contain measures aimed at reestablishing trust in information sharing, production, analysis and application.

Asked about cyber security information sharing being included, the official said the two sides are consulting with an understanding that the geographical and spatial extent of the allies' mutual defense treaty should include space and cyberspace.

As for the "Five Eyes" intelligence alliance involving the U.S., Britain, Canada, Australia and New Zealand, the official said Seoul does not consider information cooperation contingent on membership.

The official said the type of information shared between Seoul and Washington will be different from that between Washington and Tokyo, citing the joint efforts by South Korea and the U.S. in tracking North Korea's illicit cyber currency operations.