Russia's Federal Security Service claims to have thwarted a terrorist attack being planned for central Moscow, killing two suspects in the process. The FSB says three Russian citizens had just returned from the "Afghani-Pakistani region" where they had been trained in unspecified tactics and were plotting to attack the capital city.
When FSB forces surrounded their house—as so often seems to happen when Russia's security agency surrounds someone's house—a firefight broke out and two suspects were killed. This is one of the rare times that one of the suspects survived, but it's unknown what fate will befall him now that he's been captured by security forces.
It's another big "victory" for the FSB, which has been on a bit of spree lately, taking down terrorists and busting wig-wearing CIA spies like mad in the last few weeks. While many of their recent successes seem calibrated for maximum media consumption, the organization is also getting more attention in the wake of the Boston Marathon bombings, which set off a bit of an international blame game as to whether the Tsarnaev brothers should have caught before they could strike. Since the attack in Boston, however, the FSB has killed several suspected terrorists in gunfights, though (as with many American terrorist investigations) it's not clear just how close any of these groups were to carrying out actual terror operations.
Still, there is no reason Moscow should not not be concerned about terrorism threats. They have seen their share of attacks over the last two decades, including a subway bombing in 2010 that killed 41 people. The raid also happend to take place on the same days two car bombs were set off in the Republic of Dagestan, killing at least two people there. A slow-burning guerrilla war has been going on there for years, mostly unnoticed by the outside world before Boston, but it's a war that neither is close to giving up on yet.