The statement by Gen. Anatoly Nogovitsyn is the strongest threat that Russia has issued against the plans to put missile defense elements in former Soviet satellite nations.
Poland and the United States on Thursday signed a deal for Poland to accept a missile interceptor base as part of a system the United States says is aimed at blocking attacks by rogue nations. Moscow, however, feels it is aimed at Russia's missile force.
"Poland, by deploying (the system) is exposing itself to a strike - 100 percent," Nogovitsyn, the deputy chief of staff, was quoted as saying.
He added, in clear reference to the agreement, that Russia's military doctrine sanctions the use of nuclear weapons "against the allies of countries having nuclear weapons if they in some way help them." Nogovitsyn that would include elements of strategic deterrence systems, he said, according to Interfax.
At a news conference earlier Friday, Nogovitsyn had reiterated Russia's frequently stated warning that placing missile-defense elements in Poland and the Czech Republic would bring an unspecified military response. But his subsequent reported statement substantially stepped up a war of words.
Polish Foreign Minister Radek Sikorski was quoted Friday by the Polish news agency PAP as saying that Poland is open to Russian inspections because it wants to give Moscow "tangible proof" that the planned base is not directed against Russia.
U.S. officials have said the timing of the deal was not meant to antagonize Russian leaders at a time when relations already are strained over the recent fighting between Russia and Georgia over the separatist Georgian region of South Ossetia.
Russian forces went deep into Georgia in the fighting, raising wide concerns that Russia could be seeking to occupy parts of its small, pro-U.S. neighbor, which has vigorously lobbied to join NATO, or even to force its government to collapse.
"I think the Russian behavior over the last several days is generally concerning not only to the United States but to all of our European allies," said Pentagon spokesman Bryan Whitman, when asked about Russian threats against Poland as a result of the missile defense agreement.
He also suggested that earlier U.S. offers for broad cooperation with Moscow on the missile defense program may be reevaluated considering the latest developments.