WASHINGTON (Reuters) - U.S. Attorney General John Ashcroft is in intensive care at a local hospital because of a painful illness that involves inflammation of the pancreas, the Justice Department said on Friday.

Ashcroft, 61, who became the top U.S. legal officer in 2001 after a bitter confirmation battle following his appointment by President Bush, was suffering from a severe case of gallstone-caused pancreatitis, spokesman Mark Corallo said.

"He was admitted to intensive care for careful monitoring and is being treated with antibiotics," Corallo said.

Justice Department officials said Ashcroft was expected to be in the hospital for at least four or five days, and that he then could face surgery.

Ashcroft has been a target of criticism by civil liberties groups and some Democrats in Congress over the Bush administration's anti-terrorism policies adopted after the Sept. 11, 2001, attacks.

Ashcroft has defended the policies as necessary to prevent another attack and has strongly supported a sweeping anti-terror law that gave the government the power to tap phones, track Internet usage and cell phones and detain immigrants.

The illness usually begins with pain in the upper abdomen, and Ashcroft initially thought he had stomach flu, Corallo said.

It can occur when a small gallstone moves far enough into the bile duct to block the flow of pancreatic enzymes into the small intestine, causing sharp abdominal pain. The pancreas is a large gland behind the stomach.

According to the National Institutes of Health, about 80,000 cases of pancreatitis occur in the United States each year, and about 20 percent of them are severe.

"Acute pancreatitis can be a severe, life-threatening illness with many complications," it said in its information clearinghouse on digestive diseases.

CANCELED APPEARANCE IN VIRGINIA

On Thursday afternoon Ashcroft canceled a scheduled appearance in Alexandria, Virginia, to applaud the guilty verdict in a so-called Virginia jihad terror case because he believed he had a stomach flu.

"He went home and when the condition worsened, he was visited by White House Physician Daniel Parks, who advised that he go to the emergency room," Corallo said in a statement.

He said Ashcroft went to the George Washington University Hospital early on Thursday evening for an evaluation of his stomach complaints.

The illness was diagnosed after a full medical examination in the emergency room, Corallo said. "Doctors expect to know more within 48 hours," he said.

At a rally in New Orleans, Democratic presidential candidate John Kerry said of Ashcroft, "I hope everybody will say their prayers that he gets well. I don't know what the status is, but that is something that every single one of us has in our hearts and we will do that."