Police said three men, one armed with a gun, attacked security guards at a construction site on Tuesday and tied up two workers. They then grabbed the keys for the cement-mixers and made their escape.
"We do not exclude the possibility that the vehicles have been transported to the Moscow Region, where it is easier to hide them and use them than in the capital," the spokesman said.
The latest theft comes in a series of similar incident involving KamAZ vehicles in Moscow.
Last week a total of six trucks - a drop-side truck tractor, a crane truck and four dump cars - were stolen. Police believe that the crime might have been organized by a single criminal group.
Over 80 trucks and cranes have been hijacked in the Moscow Region since January this year.
