One of the US-KS early-warning satellites, Cosmos-2393 (NORAD 27613), appears to have ended its operations. The satellite, launched on 24 Dec 2002, did not perform an orbit-correcting maneuver that would normally take place in the first days of February 2007. It is still possible, however, that the satellite would return to normal operations, so for the time being it will continue to be listed as operational.
If Cosmos-2393 ended its operations, the space-based segment of the Russian early-warning system would be left with just two satellites - Cosmos-2422 (29260), launched on 21 Jul 2006, on the highly-elliptical orbit, and Cosmos-2379 (26892, 24 Aug 2001) - on the geostationary orbit.
In 2007, the Space Forces are planning to launch a new US-KS satellite into the highly-elliptical orbit. The date of the launch has not been announced yet.
UPDATE: The satellite re-entered the atmosphere at about 00:00 UTC on 22 December 2013, probably over the Pacific Ocean.