The International Olympic Committee executive board also gave final approval to introducing tests for the banned drug erythropoietin, or EPO, at the upcoming Sydney Games.
The IOC trimmed the preliminary field of 10 cities for the 2008 Games to a shortlist of five official candidates.
Eliminated from the race were Bangkok, Thailand; Cairo, Egypt; Havana; Kuala Lumpur, Malaysia, and Seville, Spain.
The cutoff came 10@1/2 months before the full IOC selects the 2008 host city at its session in Moscow in July 2001.
The IOC said Beijing, Osaka, Paris and Toronto "reached an overall grade above the established benchmark" for Olympic bid cities.
The board accepted Istanbul, making a third consecutive bid, as a fifth candidate city, even though it did not pass the grade.
The EPO tests were endorsed Sunday by the IOC legal commission, which recommended their final approval Monday by the executive board.
A combined urine and blood test for EPO was backed earlier this month by the IOC medical commission and outside scientific experts. But final authorization was required by the legal commission and executive board.
IOC medical commission chairman Prince Alexandre de Merode said at least 400 EPO tests will be conducted from Sept. 2, the day the athletes' village opens in Sydney, until the close of the games on Oct. 1. In addition, 3,400 standard urine tests will be carried out, he said.
"I think (the EPO test) will be a very good impact on the many athletes who do not cheat," IOC vice president Kevan Gosper of Australia said. "For those who do cheat, I hope it scares the heck out of them."
The field for the 2008 Games will include cities from Asia, Europe and North America.
Beijing, which lost by two votes to Sydney in the 1993 ballot for the 2000 Games, is widely considered the city to beat.
With its population of 1.26 billion, China offers a vast, untapped market for the Olympics. But China's human rights record could again be a major issue, as pro-Tibet groups have already threatened to wage a campaign against Beijing's bid.
IOC executive Jacques Rogge said Beijing, Paris, Toronto and Osaka were approved unanimously, while Istanbul made the cut by a majority vote.
"There was no ranking system," he said. "The four cities were above the bar. Istanbul was just under the bar. The executive said, `We can push it over."'
While the IOC can still eliminate candidates before the July vote, IOC director general Francois Carrard said it's expected all five cities will go the distance.
The new "candidate acceptance procedure" was introduced as part of the reforms adopted by the IOC last year following the bribery scandal centering on Salt Lake City's winning bid for the 2002 Winter Games.
The proess is designed to save money, weed out no-hopers and prevent a repetition of the payoffs and favors exposed by the Salt Lake affair.
Gifts and member visits to bid cities are prohibited under the new system.
The cities went through a preliminary screening process to determine whether they met the minimum organizational requirements for staging the Olympics.
The IOC will appoint an evaluation commission to visit the sites and assess their capabilities.
EPO, the drug at the heart of the Tour de France doping scandal in 1998, is believed to be widely used by athletes in endurance events such as long-distance running, swimming and cycling.
Injected in synthetic form, EPO enhances stamina by increasing the number of red blood cells, which carry oxygen to the muscles. Experts say it can improve performance by up to 15 percent.
French researchers developed a urine test that can provide direct proof of EPO use, while Australian scientists devised a blood test which offers indirect evidence.
In Sydney, an athlete will be considered guilty of EPO use only if both tests are positive.
In addition to the EPO tests, the new World Anti-Doping Agency is conducting around 2,000 unannounced, out-of-competition tests before the Sydney Games. All 28 Olympic sports federations have signed up for the tests.
©2000 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed