The chances of National Security Agency leaker Edward Snowden finding an easy path out of Moscow's Sheremetyevo Airport looked increasingly slim, as the former security contractor and fugitive waited for responses to asylum requests he said he has submitted to more than 20 countries.

Following is a list of the countries to which Mr. Snowden has applied and their public responses to date. Those that have said his application could be considered only if he reaches their territory are listed as "unlikely" because Russia...