MOSCOW — The Kremlin showed its military might off the European coastline yesterday as Russian warships and nuclear bombers test-fired missiles close to the Iberian Peninsula during the first major military maneuvers in the Atlantic since the Cold War.

Although Russia gave warning of the exercises to North Atlantic Treaty Organization countries, the operation is likely to cause an element of disquiet in the West, more for political than military reasons. As East-West relations have soured, Mr. Putin responded last year by ordering a resumption of long-range bomber patrols in international airspace. He also threatened to retrain part of Russia’s considerable nuclear arsenal on European targets if a proposed American missile defense shield, to be built in Poland and the Czech Republic by 2012, is not scrapped. Meanwhile, Russian prosecutors yesterday opened a criminal investigation into an opposition presidential candidate, Mikhail Kasyanov, for his alleged forging of signatures to support his bid.

An aide to Mr. Kasyanov, a former prime minister, said prosecutors were applying “political pressure” to sabotage his bid.