Tokyo stocks plummeted Monday morning, with the key Nikkei average dipping below 9,500 at one point, as the tumble in European stocks Friday made investors nervous ahead of the restart of U.S. trading.

The 225-issue Nikkei average closed Monday's session at 9504.41, resetting the postbubble closing low that was marked just five days ago. The close was down 504.48 from Friday.

In the morning, the Nikkei fell 488.20 points, or 4.88 percent, to end at 9,520.69. It hit 9,447.76 in early trading, down 561.13 points. The Topix index of all first section issues slipped 38.07 points, or 3.68 percent, to 995.74.

"Bearish sentiment enveloped the Tokyo market ahead of the reopening of the U.S. stock market," said Muneyuki Ichihara, investment information manager at Nomura Securities Co. "In addition, the yen's sharp rise against the dollar and Friday's tumble in European stocks triggered the selloff in Tokyo."

In New York, equities trading was to resume Monday for the first time since the devastating attack on the World Trade Center and the Pentagon on Sept. 11.

In Europe, stocks tumbled Friday as investors grew fearful that the U.S. market may plunge when it reopens, traders said. The key indexes of Frankfurt and Paris stocks dropped about 5 percent each.

In Tokyo, airlines continued to lead the fall, diving 9.73 percent as investors expect the industry to be badly hit following the hijackings in the United States.

All Nippon Airways hit a new year-to-date low.

Automakers, which heavily depend on sales in the U.S., also met with selling, with Toyota Motor, Honda Motor and Nissan Motor hitting new year-to-date lows.