Wednesday September 12 11:47 AM ET

NEW YORK (Reuters) - A police officer was pulled from the steel and glass wreckage of the World Trade Center on Wednesday and New York Mayor Rudolph Giuliani said rescue workers were scrambling to save others trapped in the mountain of rubble.

Hundreds of emergency workers using scent-sniffing search dogs and construction equipment to remove tons of smoldering debris, rescued a Port Authority policeman from the destruction of the city's once-mighty symbols of financial power. The policeman was listed in critical condition at a hospital.

Two other officers were rescued late Tuesday hours after hijackers slammed planes into the World Trade Center's 110-story twin towers as part of a coordinated strike that also left the Pentagon near Washington in flames, officials said.

Compared with the thousands who were feared dead after the worst attack on U.S. soil since Pearl Harbor, the number of rescued survivors was minimal but helped lift the spirits of shocked Americans as attention focused on saving lives.

Late Tuesday, the two other police officers were pulled from the wreckage and two other people trapped in the debris -- who have yet to be accounted for as rescued -- used cell phones to contact rescue workers.

As many firefighters poured over the mountain of debris with listening devices and scores of others rested exhausted atop the building's wreckage in Lower Manhattan, Giuliani said rescue teams were close to pulling a fourth survivor out on Wednesday.

``We have been successful in recovering one other person. Hopefully, we will be able to recover a fourth one,'' Giuliani told a news conference.

``We are in the process of doing everything we can to locate other people. That will be the focus of our attention,'' Giuliani said.

Television network ABC reported from the scene that eight people have been pulled from the rubble, including a group of six firefighters, and cited the mayor as saying that as many as 1,000 people could still be trapped in each tower's rubble.

``The focus right now is on search and rescue in the hopes that we can pull other people out of the debris and save more lives,'' New York Gov. George Pataki said.

Giuliani said 120 trucks full of debris were removed from the scene overnight and said more will be removed throughout the day.

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