The New York Times reports: A senior Russian general threatened on Wednesday pre-emptive attacks on missile-defense sites in Poland and elsewhere in Eastern Europe in the event of a crisis, underscoring the Kremlin’s opposition to the Obama administration’s plans and further undermining relations between the countries.

While Russian officials have said previously that the antimissile sites could become targets in the event of war, the threat of a pre-emptive attack was new.

The remarks from the general, Nikolai Makarov, the chief of the General Staff of the Russian armed forces, coming just days before Prime Minister Vladimir V. Putin is set to assume the presidency again, might signal a move to a more muscular foreign policy than that pursued by the departing president, Dmitri A. Medvedev.

They also seem likely to further inflame an already tense relationship. In recent months, the Kremlin has resisted Washington’s entreaties to pressure the government of President Bashar al-Assad in Syria and has given a cold shoulder to the new American ambassador, Michael A. McFaul, with prominent commentators and politicians accusing him of trying to foment revolution in Russia.

General Makarov was speaking at a conference in Moscow on antiballistic missile policy, hosted by the Russian Ministry of Defense. In his speech, one of many spelling out opposition to the plan, he went on to specify the type of Russian short-range missiles that might target locations in Eastern Europe.