Three suspects will appear in court in Kenya next week after six elephants, including four juveniles, were found shot dead in a private reserve in one of the worst poaching incidents in several years.
A wildlife official said that it is thought that the killings were at least partly motivated by revenge against officials because the calves, not having tusks, had no value to poachers.
The poachers "would have no reason for killing juveniles. They are trying to hit back at the authorities," the official said.
The adult elephants had their tusks removed.
Kenya Wildlife Service said its rangers exchanged gunfire with poachers on Saturday evening.
Three suspects were arrested but others are thought to be still at large.
The wildlife service linked the killings to the recent arrest of poaching suspects.
"We arrested 15 poachers the previous week for killing an elephant in the same area," William Kiprono, the service's director was quoted as saying in the Daily Nation newspaper.
The animals were killed in a southwestern reserve on the edge of the Tsavo National Park.
Kenya is battling an upsurge in the slaughtering of elephants and rhino. Since the start of the year, 65 elephants have been lost to poaching in Kenya, according to figures from the wildlife service, which recorded 302 slayings for the whole of 2013.
The service has been battling accusations that poaching ringleaders have been allowed to act with impunity. Five of its officials were suspended this month in a probe into mismanagement.