Kerry spoke at the U.S. Embassy in London, Politico reported.
"If you are the spouse of a U.S. citizen, your visa application will be treated equally. If you are the spouse of a non-citizen, your visa application will be treated equally. If you are in a country that doesn't recognize your same-sex marriage, then your visa application will still be treated equally at every single one of our 222 visa processing centers around the world," he said.
In a statement, the State Department said the only requirement is that a marriage be legal in the jurisdiction where it was performed. Those who are engaged but cannot marry legally where they now live can seek fiance visas.