The Soviet Union warned Friday that any attempt by NATO to modernize its short-range tactical nuclear arsenal in Europe would seriously threaten the latest round of conventional arms reduction talks in Vienna.

At a news conference, Deputy Foreign Minister Viktor Karpov reaffirmed an offer made earlier this month by Foreign Minister Eduard Shevardnazde to hold a parallel set of talks aimed at reducing tactical nuclear weapons.Such weapons are not included in the mandate of the 23-nation Conventional Forces in Europe talks - negotiations between NATO and the Warsaw Pact that opened in the Austrian capital Thursday.

"Tactical nuclear weapons are not on the agenda but what will be discussed are dual capable weapons systems. This is a step in the right direction but it is not yet sufficient to build a security system in Europe on a solid foundation that would rule out surprise attack and large scale operations," Karpov said.