WASHINGTON (AP) - After a day of high-stakes questions and too many wrong answers, Tom Ridge gathered the government's top crisis officials at the White House Thursday for an extraordinary 62-minute public briefing _ what the new homeland security director hoped would be a calming "information overload."

Law enforcement agencies were chasing some 300,000 terrorism leads, while health officials were starting to stockpile 12 million doses of anthrax-fighting drugs and 300 million doses of smallpox vaccines, the officials announced.

There's no reason for people to hoard antibiotics, said Surgeon General David Satcher.

Pranksters with their phony anthrax threats face up to five years in prison, said Attorney General John Ashcroft. Four were charged this week alone. "I hope we throw them in jail and we ought to throw away the key," said Ridge.

The post office is sending every household a postcard of instructions on spotting and handling suspicious mail, said Postmaster General Jack Potter.

The coordinated information offensive came one day after officials bombarded Americans with alarming messages on the anthrax scare on Capitol Hill _ everything from the bacterium drifting through Senate ventilation ducts (it wasn't) to the powder being so sophisticated that it looked like the handiwork of terrorists developing weapons of mass destruction (it wasn't).

"We've watched it. There has been some concern. There were mixed messages," Ridge said in an interview after the briefing, which was televised live on cable news stations.

On the job just 10 days, Ridge promised to do more briefings _ and frequently.

"It was like information overload," he said. "In a country that craves information, it's better to give you too much than not enough."

President Bush created the Office of Homeland Security and put Ridge, the former Pennsylvania governor, at its helm after the Sept. 11 attacks on New York and Washington. From his cubbyhole just down the hall from the Oval Office, Ridge is supposed to coordinate the counterterrorism work of 46 separate government agencies.

On Wednesday, he added public information officer to his job description, saying the government needed a central voice to guard against "defective information."

"Instead of speculating, we would like to focus on the facts," Ridge said.

Among them:

_Anthrax has not been found in government buildings besides those in the Senate and New York governor's offices, Ridge said.

-The anthrax sent to Senate Majority Leader Tom Daschle "looked to be run of the mill" and not something whose spore size or coating had been successfully manipulated for use as a weapon of mass destruction, said Bill Winkenwerder, assistant secretary of defense for health affairs.

-Of the "thousands and thousands and thousands" of people tested, only six tested positive for anthrax infection, said Ridge, and all but one, who already died, are expected to recover fully.

-The government is expanding its stockpile of Cipro, the best-known treatment for anthrax, from 2 million doses to 12 million, said Satcher. And the Food and Drug Administration is getting word to doctors that penicillin and tetracycline are also effective for anthrax. "So far all of the strains that have been identified are sensitive to the antibiotics that we have," the surgeon general said. He appealed to Americans to "understand the harm that can be done if people hoard antibiotics and use them inappropriately so that we develop more resistant strains" of the deadly germ.

-The government is looking to buy 300 million doses of smallpox vaccine _ enough to inoculate every American _ but has not yet decided such a mass vaccination will be necessary. "We looked at potential challenges to this country and smallpox is one of them," said Ridge. "We decided to prepare for that challenge."

Added Satcher, "We haven't seen a single case of smallpox in the world since the late 1970s. ... You're always hesitant to immunize people against a disease unless you're certain, fairly certain, that there is going to be a risk."

-The FBI has, in the past 18 days, responded to 3,300 cases of suspected chemical or biological agents, including 2,500 that involved anthrax threats, said Director Robert Mueller. In an average year, the FBI handles 250 cases total.

-Mailing anthrax is a terrorist act but the FBI doesn't yet know who is responsible "to the extent that they could be put into an indictment or arrests be made," Mueller said.

-Preliminary tests on anthrax spores mailed to Florida and New York show they came from the same strains, said Mitch Cohen, director of the Centers for Disease Control and Prevention. They have not yet been compared to spores from Daschle's office.