"The World Bank urges the Government of Sri Lanka to hold full and transparent investigations of incidents of violence against media," the World Bank said.
"The World Bank expressed grave concern about the growing incidents of violent attacks on the media in Sri Lanka, including the brutal killings of several journalists," the lender said in a statement.
"Free and independent media is fundamental to the sustainable economic development of Sri Lanka.
"Violence against media has a profoundly negative impact on the ability of the media to fulfill its core watchdog function and to carry out its role as a medium of accountability and a reflection of citizen voice."
The statement came after the killing of Lasantha Wickremetunga, editor of The Sunday Leader, a newspaper that was strongly critical of the government.
Just days earlier, an armed group had stormed a studio complex of Maharaja Television, shot at equipment and torched its main control room.