NEW YORK (AFP) - breaking news

Two planes smashed within minutes of each other into the twin towers of New York's landmark World Trade Center on Tuesday, media reported.

A witness reported a "sonic boom" as a commercial passenger jet collided into the north tower of the 110-story building between the 80th and 85th floor.

Within minutes another commercial plane ploughed into the south tower, with television footage showing flames and smoke billowing across the New York skyline.

Ira Furman, a former National Transportation Safety Board spokesman, indicated that the crashes were not accidental.

He told CNN there was no indication that normal air traffic would be in the area.

Planes would "normally be clearing the World Trade Center by a few miles," he said.

The large passenger commercial jet was teetering towards the tower before it "embedded in building," New York resident Jeanne Yurman told the network.

The World Trade Center consists of two 110-story skyscrapers and are New York's tallest towers. One of the towers is just six feet (two meters) taller than the other.

About 40,000 people work inside the two-building center; more than 150,000 people enter the complex every day for business and pleasure.

On February 26, 1993, a terrorist bomb exploded in building number one's lower level.