NEW YORK (Reuters) - A ray of hope emerged from the destroyed World Trade Center on Tuesday as two police officers were pulled alive from the rubble, and others trapped inside made desperate pleas for help via cell phones.

New York Mayor Rudolph Giuliani said two police officers of the Port Authority of New York and New Jersey, which had its headquarters inside the trade center complex, were pulled out alive.

Giuliani, along with New York Police Commissioner Bernard Kerik, said emergency services were receiving phone calls from people trapped inside the remains of the 110-story twin towers.

A police department source told Reuters the trapped callers have dialed the 911 emergency number and were trying to describe to police where they were trapped.

Giuliani said the callers are also saying there are other people alive nearby them.

However, doctors manning the emergency triage center at the NYU Downtown Hospital said they saw mostly firefighters coming in for treatment. “We keep hearing word that they are finding pockets of people, and that’s why we’re all excited and standing around here. But I just walked over there an hour ago and it didn’t seem like we were getting real close to that,” said Dr. Harold van Bosse, speaking from the Mount Sinai NYU Medical Center’s NYU Downtown Hospital.