[Helmut Kohl], in his first public involvement in the controversy, has informed the U.S. government that the "form and substance of the discussion" of the issue in the U.S. media were "not very helpful," chief government spokesman Friedhelm Ost said in a four-page statement.

That criticism referred to a report in Sunday's New York Times revealing the name of a West German company that Washington says played a central role in building the Libyan plant, West German officials said. The Times story was based on a leak by U.S. administration officials of data that the United States previously had asked West Germany to keep secret, according to U.S. and West German officials.

The statement made clear that West German investigators cannot proceed further unless they receive the "detailed information" that has been "promised by the U.S. side." The Finance Ministry will contact U.S. authorities on Jan. 10 for further discussions if no additional data are provided by then, it said.