Boston Mayor Thomas Menino this evening received condolences for the Boston Marathon bombing from former New York City Mayor Rudy Giuliani, who compared it to the Sept. 11 World Trade Center attack.

"One of the images that I take away from yesterday, having watched it all day, were your firefighters, your police officers and some of your citizens running right into the fire, and that reminded me of my firefighters and my police officers who ran into the building," Giuliani told Menino, speaking mayor-to-mayor in a joint interview with "World News'" Diane Sawyer.

Mayor Menino agreed, adding firefighters and EMS to the list of American heroes in Boston Monday.

"They reacted instantly and helped save lives," Menino said. "When it blew up, they moved quickly, and I'm very proud of what the first responders did yesterday afternoon."

"People of Boston should be, too," Giuliani said. "They should be very proud of their citizens, all of whom reacted in a very, very brave way, and I was very heartened by that."

The brief meeting between the two mayors of major American cities was a surprise for Menino, who did not know Giuliani was listening in on his interview with Sawyer.

Before being joined by Menino, Giuliani recalled being in London for the 2005 bombing that killed 52 civilians in the train system.

"They caught those people in less than a day," Giuliani said. "They caught them on tape.

"Now hopefully, they have tapes like that [in Boston]," Giuliani said. "They've got a lot of surveillance cameras in Boston - more than New York, less than London."

He suggested it was possible, too, that a spectator might have incidentally caught the moment on camera.

His advice to the people of Boston was to "go about their lives."

"They should not let whatever form of terrorist this is, they shouldn't let them win, because this is what they're trying to do. They can't capture us. They can't overwhelm us. They can't destroy us. All they can do is frighten us and try to stop us from doing the things that make us a great country. We shouldn't let them do that," the former New York City mayor said. "My heart goes out to them."

Menino told Sawyer that authorities continued to investigate the attack that left three dead and more than 170 wounded, going over the area with a "fine-toothed comb," and that a pressure cooker might have been involved.

"We don't have any other information that we can give to the public at this time, but I know the FBI, the Boston police [and] the state police are all working very closely on this investigation," Menino said.

He echoed Giuliani by saying he was optimistic that footage from surveillance and private citizens' cameras would allow officials to find the attacker.

"We have a lot of video on this, and we're looking at all that video and asking the public who might have cameras to give them to the Boston police so they can look at the information," the five-time Boston mayor said. "That's the most camera-ed area in the city of Boston."

Putting aside the deep-rooted baseball rivalry between the two cities, New York's Yankee Stadium planned to play the song "Sweet Caroline" during the Yankee game Tuesday night as a tribute to Boston, where the song is a Fenway Park tradition for the Red Sox.

"That's a historic moment when that song goes off at the ball game," Menino said.

"We are all together tonight," Giuliani assured him.