More than half the tickets for the Summer Olympics remain unsold, with corporate sponsors buying far fewer seats than four years ago, organizers in Athens said yesterday.

The figures seemed to reinforce some of the worst fears for the Aug. 13-29 Games: Security worries and a shaky global economic recovery leaving unfilled venues for all but the top events.

But organizers staked faith in the Greek tradition of last-minute planning and noted that their revenue goal was within reach even with slow sales.

A total of 5.3 million tickets were set aside for Athens -- 3 million to the public and 2.3 million for International Olympic Committee officials, sponsors and others.

But just 1.83 million tickets have been sold so far. Officials would not give a breakdown of how many were for the public and the "Olympic family."

"The stadiums of the Olympic Games. . . . must be and will be full. We firmly believe that this is the image of the country we want to give to the outside world," said Marton Simitsek, a top Olympic planner.

The revenue picture is brighter. Organizers said their goal was to make $223 million from tickets, which have been sold in various periods since May 12, 2003. About $167 million has been made. They refused to give further details.

Meanwhile, Spain's Santiago Calatrava, the architect who designed the glass-and-steel roof for the main Olympic stadium, is certain it will be ready on time.

The stadium roof has been mired in delays and there were fears it would not be completed in time for the Games.

Russian Banned

Russian sprinter Anastasiya Kapachinskaya was banned for two years after testing positive for a steroid at the indoor world championships, where she won the 200-meter gold medal.

She said she will not appeal the ruling that will prevent her from competing in the Athens Olympics. She will cooperate with the World Anti-Doping Agency in the fight against performance-enhancing drugs.

"It's an accident," she said at a news conference in Moscow. "I swear I did not take any banned substances."

Natalya Safronnikova of Belarus now takes first place in the world indoor 200, followed by Svetlana Goncharenko of Russia and Karin Mayr-Krifka of Austria.

Kapachinskaya, who won the 200 in Hungary in March, tested positive for the steroid stanozolol during the competition. A second test also came back positive.

U.S. 2nd in Pentathlon

Russia won its first gold medal in the men's relay at the world modern pentathlon championships in Moscow, with the United States rallying to finish second.

The American team of Chad Senior, Vakhtang Iagorashvili and Scott Christie was eighth in shooting, second in fencing and sixth in the swimming relay. It performed flawlessly in the equestrian competition. South Korea won the bronze.