BANGKOK (Reuters) - Thai authorities charged former Prime Minister Abhisit Vejjajiva on Thursday with giving orders to use live ammunition that led to civilian deaths during a military crackdown on an anti-government protest in May 2010.

The Department of Special Investigation (DSI), part of the Justice Ministry that has a similar role to the U.S. Federal Bureau of Investigation, charged Abhisit and former Deputy Prime Minister Suthep Thaugsuban for their role in the events.

"They were charged with allowing security forces to use weapons and live ammunition that eventually led to the death of civilians," said DSI chief Tarit Pengdith.

The protesters, supporters of former Prime Minister Thaksin Shinawatra, who was ousted in a coup in 2006, took to the streets of Bangkok from March to May 2010 to demand early elections. More than 90 people died during the protest.

Thaksin' sister, Yingluck Shinawatra, is now prime minister. Her Puea Thai Party beat Abhisit's Democrat Party in an election in July 2011 and he became leader of the opposition.

(Reporting by Sinthana Kosolpradit; Writing by Amy Sawitta Lefevre; Editing by Alan Raybould and Jonathan Thatcher)