According to Inside the Games: A total of 699 athletes have been put forward by their National Federations to compete at the 2016 International Association of Athletics Federations (IAAF) World Indoor Championships in Portland.
The event will take place March 17-20.
Preliminary entries include a total of 403 men and 296 women from 154 Federations, which would make the event in the American city larger than the previous two editions on the continent.
A total of 537 athletes from 93 countries competed the last time the Championships visited North American soil, when Canadian city Toronto staged the event in 1993.
Meanwhile at the 1987 World Indoor Championships, which were held in US city Indianapolis, 419 athletes from 85 nations took part.
The Championships will take place without Russia after they were suspended by the IAAF in November.
The All-Russia Athletic Federation (ARAF) were handed the ban following the recommendation of the World Anti-Doping Agency (WADA) Independent Commission, who found evidence that Government officials were involved in helping Russian athletes avoid detection for doping and, in some cases, letting them escape punishment after they had failed tests.
The IAAF has set-up a five-member inspection team, led by Norwegian anti-doping expert Rune Andersen, to oversee reforms in Russia and a number of conditions must be met before they are allowed back into the international fold.
At the moment, the inspection team is due to report its findings at the IAAF Council meeting in Cardiff on March 27, with Russia also facing the prospect of missing the Rio 2016 Olympic Games.
The IAAF are expecting a further reduction in numbers when the preliminary list of entries is whittled down to the final participants.
However, they anticipate the Championships will have a bigger field than that seen at the last edition in Sopot in 2014, when 539 athletes from 134 nations competed in the Polish town.