NAIROBI, Kenya  For a moment, the pirates must have thought that they had really struck gold  Somalia-style.

The gun-toting, seafaring thieves, who routinely pounce on cargo ships bobbing along on the Indian Ocean, suddenly found themselves in command of a vessel crammed with $30 million worth of grenade launchers, piles of ammunition, even battle tanks.

But this time, they might have gotten far more than they bargained for. Unlike so many other hijackings off the Somali coast that have gone virtually unnoticed  and unpunished  the attack Thursday evening on the Faina, a Ukrainian vessel bringing military equipment to Kenya, has provoked the wrath of two of the most powerful militaries on the planet.

The United States Navy was in hot pursuit of the ship on Friday. And the Russians were not far behind.