The Mexican government and the Federal Communications Commission announced an agreement this week to help crack down on smartphone robbery, which authorities said make up about 40 percent of all robberies in Washington and other big American cities.

FCC Chairman Julius Genachowski said in a statement that the agreement, announced Tuesday, is aimed in part to promote collaboration in blocking reactivation of stolen devices to show that taking them “does not pay.”

D.C. Police Chief Cathy L. Lanier called the plan “a huge step” toward ultimately curbing the thefts of devices and injuries to victims.

The announcement came three days before D.C. police issued a report listing arrests in five recent robberies here.

Three of the five involved cellphones. One occurred Nov. 9 in the 5700 block of East Capitol Street SE. The other two were Monday in the 1100 block of 30th Street near the C&O Canal in Georgetown and Tuesday in the 1500 block of Benning Road NE.