U.S. Alert After London Blasts

While top U.S. counterterror officials say there are no plans to increase the current alert status following the attacks in London, cities around the country displayed a heightened state of alert.

President Bush, in Scotland for the G-8 summit, urged vigilance.

The Homeland Security Department says there are also no indications of an imminent attack on U.S. interests. A Homeland Security official tells CBS News Correspondent Peter Maer the government's "interagency incident management group" is meeting to "assure full situational awareness." Other officials are monitoring events in London from the White House Situation Room. A Homeland Security spokeswoman says the department is in close contact with British intelligence and other agencies.

President Bush had a 10-minute video conference call with National Security advisers back in the U.S., reports CBS News White House Correspondent Mark Knoller.

In a brief speech, Mr. Bush warned Americans to be "extra vigilant" as they head to work after the deadly explosions in London.

"The war on terrorism goes on," he said. "We will not yield to these people. We will not yield to the terrorists."

Terrorism analyst Neil Livingstone tells CBS radio affiliate WTOP in Washington that "it's not a question of if, but when" the U.S. will be attacked again by al Qaeda.

"This is a war that's going to have peaks and valleys," Livingstone said. "Since 9/11, nothing has happened. A lot of Americans think that Osama bin Laden's on the run, therefore we have nothing more to fear."

The explosions on London's transit system prompted heightened security on Washington's subway system. A Metro spokeswoman said officials were "ramping up security immediately," including the use of bomb sniffing dogs. Officers will have a higher visibility, she said, and will be carrying machine guns.

At the Farragut West station, the one closest to the White House, Maer saw transit police using announcements and flashing signs to remind passengers to watch for anything suspicious.
About 1.2 million people a day ride Washington's buses and trains.

In New York, Gov. George Pataki said transit systems would operate normally Thursday.

"Just show a little bit more alertness, look around, if there are any unattended bags or packages or backpacks, let the authorities know," he told WCBS-AM.

In Los Angeles, a police official said police had activated a special command center and officials were meeting to decide whether to upgrade security levels around the city.

A spokeswoman for the Chicago Transit Authority said transit officials were working with Chicago Police on additional security measures. CTA spokeswoman Kimberly Myles said announcements were being made to riders to be aware of their surroundings and to alert transit workers about suspicious packages.

In Massachusetts, Gov. Mitt Romney raised the security level on Boston's transit system as a precaution.

"Amtrak has increased its security threat level," spokesman Clifford Black told WTOP. "We're putting more resources into our security efforts ... We'll continue at this heightened security level until we have a better understanding of the events in London."