CALCUTTA, India - Trains have killed two elephants in separate collisions over the past week in India, officials said Sunday.

A passenger train hit an elephant as it crossed a track in the northern Dooars region of eastern India's West Bengal state Saturday night, said Tapas Bose, a forest officer in the district.

A few days earlier, another elephant died after a freight train knocked it over in a densely forested area also in the Dooars region, Bose said. Trains have killed at least six elephants in the area since January, he said.

The Dooars region, home to many wild animals, is about 400 miles north of the state capital, Calcutta. Animal rights activists have been demanding that train drivers be ordered to slow down while crossing the Dooars.

A government committee set up after protests by non-governmental organizations has recommended that trains travel at a maximum speed of 18 mph to 25 mph in the forests, especially areas frequented by wild elephant herds, said Animesh Basu of the Himalayan Nature and Adventure Foundation.

"The idea was that whenever the train drivers spot any animal on or crossing the tracks, they could bring the train to a halt," Basu said. "But the train drivers hardly follow this order resulting in the deaths of so many animals."