Cambodia's Prime Minister Hun Manet on Monday launched a controversial $1.7 billion canal project that aims to provide a new link from the Mekong River to the sea.

At a launch event in Prek Takeo, southeast of the capital Phnom Penh, Manet called the 180-kilometer project "historic," as fireworks shot into the air and drums sounded.

"We must build this canal at all costs," he said.