WASHINGTON -- Six thousand police officers, 2,500 military personnel, and dozens of federal security agencies will patrol a locked-down capital during next week's presidential inauguration, which outgoing Homeland Security Secretary Tom Ridge promised yesterday would be the most secure in history.

"This is not an on-the-job training exercise," Ridge said during a press preview of security gadgetry on the National Mall yesterday. "We're as prepared as possible to thwart any attempts at terrorism."

Ridge, who led a tour of a half-dozen mobile command units and met with two enthusiastic bomb-sniffing German shepherds, said there was no intelligence that specifically warned of an attack during the Jan. 20 inauguration, and that the color-coded terror threat level would not be raised.

About 250,000 people are expected to attend the first inauguration ceremony since the Sept. 11, 2001, terrorist attacks, according to the Secret Service, which is in charge of security for the event. An additional 500,000 are expected to line the parade route along Pennsylvania Avenue.

Protest groups continued to complain that the security arrangements, whose total cost Ridge said he didn't know, are preventing them from mounting effective demonstrations.

Even a pro-Bush group, freerepublic.com, yesterday criticized a Secret Service edict that prevented members from waving miniature American flags during the inaugural parade.

Most of downtown Washington will be impassable during the ceremony, parade, and inaugural balls.

The city's subway system will skip two downtown stations, and the region's airspace will be more restricted than usual on the day of the event.

Blackhawk helicopters and fighters will patrol the skies, and the Coast Guard plans to step up security on the Potomac River. Washington police have told residents of some streets close to the parade route or inaugural balls that they may need to show photo identification to get to their homes during the festivities.

Officials said they hope to keep the city as open as possible under the circumstances.

"I don't think people will notice an encampment mentality here," said Army Major General Galen B. Jackman, commander of the military district of Washington.

Jackman, who will lead the inaugural parade, said that in addition to 2,500 uniformed personnel on security and medical duty, an additional 4,700 service members would participate in the inauguration in a ceremonial role.

Meanwhile, antiwar protesters threatened legal action yesterday over a Secret Service decision that prevents them from using wooden supports to hold signs and banners because they could be used as weapons.

Bill Hackwell, a spokesman for the leftist International ANSWER, an umbrella organization for anti-Bush protesters, said his group would file a lawsuit today to challenge the ban on the grounds that it violates First Amendment rights.

"They're saying it's a security issue; we think it's a political issue," Hackwell said.

The group also plans to challenge the Park Service's process for issuing permits.

"Over 95 percent of Pennsylvania Avenue will be people who had to buy tickets," Hackwell said. "They've made it a pay-per-view event."

On the other end of the political spectrum, Kristinn Taylor, the head of Free Republic's Washington branch, said that the conservative group had been notified its members would not be allowed to wave wooden crosses or small American flags during the parade.

"A lot of these rules were not targeted at preventing acts of terrorism," Taylor said. "They were aimed at the left-wing protesters, but the law has to be applied equally to everyone."

Taylor said he'd rather the Secret Service allow both camps to wave banners.

"If we're allowed to hold our American flags," he said, "then they can hold their hammer and sickle flags or whatever."

ANSWER's Hackwell said the Park Service decided on Monday to allow the group to build bleachers for antiwar demonstrators on the group's 210 feet of space bordering the parade route.

The group expects a few thousand demonstrators to turn out for the protest.

Police Chief Charles H. Ramsey, whose department was criticized by the City Council last year for heavy-handed policing and mass arrests at an antiglobalization protest in 2002, said the First Amendment rights of demonstrators would be respected.

? Copyright 2005 Globe Newspaper Company.