Thieves have stolen nearly $300 million from a bank in Baghdad, police and a bank official said Thursday, in what is probably one of the biggest thefts in Iraq since the 2003 war to topple Saddam Hussein.

Police said the thieves were three guards who worked at the private Dar Es Salaam bank in Baghdad's Karrada district.

They said that when bank employees arrived for work on Wednesday they found the front door open and the money gone. The guards, who normally slept at the bank, had also disappeared, they said.

An official at the bank said about $300 million in U.S. dollars had been stolen, as well as 220 million Iraqi dinars ($176,000). He declined to give further details.

Police said the Interior Ministry and the Finance Ministry had set up a committee to investigate the theft.

It was not immediately clear why the bank had so much cash on hand, but Karrada is a key commercial district in Baghdad.

Ever since the U.S.-led invasion of Iraq, most transactions have been conducted in cash because of limited facilities to transfer money through banks or other financial institutions.

Huge amounts of money were looted from Iraq's banks during the invasion.