GUIYANG, June 14 -- Four people have been confirmed dead after a building in southwest China's Guizhou Province partially collapsed on Sunday morning.

Part of a nine-story apartment building built two decades ago collapsed in Zunyi City collapsed at 5:58 a.m.

Four people were found dead and three others injured as of 10:30 p.m., as rescuers wrapped up a 15-hour search effort.

Authorities has opened probe into the cause of the collapse and vowed to hold relevant party accountable.