12 people, including 11 policemen, were injured Sunday in a grenade attack reportedly conducted by a local gang for extorting protection money in the southeast of Guatemala City, news reaching here reported.
The fragmentation grenade was tossed at a group of policemen when they were standing outside the buses of La Union Company.
The policemen were guarding the buses after the company was blackmailed to pay money to the gang, known as "Maras," or face killing of its bus drivers.
The injured were immediately taken to a nearby hospital.
So far, more than 100 drivers and assistants have been killed this year, according to the Guatemalan government.