WASHINGTON (CNN) - President Bush signed a tough new identity theft bill Thursday that sets mandatory jail time for people convicted of stealing someone else's identity.

"Last year nearly 10 million Americans had their identities stolen by criminals who robbed them and the nation's businesses of nearly $50 billion," Bush said.

The law, the Identity Theft Penalty Enhancement Act, creates the charge of aggravated identity theft, which carries a required two-year prison term.

When identity theft is connected with a terrorism case, such as providing a terrorist with a false passport, the mandatory prison term is five years.

"It reflects our government's resolve to answer serious offenses with serious penalties," Bush said of the new law.

He noted that protecting citizens from identity theft is a "solemn responsibility" of government and vowed that the era of identity thieves receiving little or no time in prison "ends today."