China on Tuesday condemned the hostage killing in southern Philippines which left at least 37 people dead.

"We are shocked by the incident. We denounce it and extend our sincere sympathy to the families of the victims," Foreign Ministry spokesman Qin Gang told a regular press briefing.

At least 37 people were killed on Monday afternoon in Maguindanao of southern Philippines when an ambush and execution occurred.

The incident happened while a convoy of at least 40 journalists and supporters of Buluan town Vice-Mayor Ismael Mangudadatu were on their way to register him as the candidate for the post of Maguindanao Governor against current governor Andal Ampatuan's sonin the May 2010 elections.

Philippine President Gloria Macapagal-Arroyo on Tuesday placed three provinces in southern Mindanao region under the state of emergency following Monday's bloodshed.